A small swelling is mild in a dog. Tumors in dogs: types, symptoms and treatment

There are benign and malignant tumors.

Benign tumors have the so-called expansive growth. It is characterized by the fact that the normal tissues surrounding the tumor are compressed and moved away (or moved apart). Due to this, there are clear boundaries between the tumor and surrounding tissues and a capsule is formed, within which the tumor grows. The histological structure of benign tumors is similar to the structure of the original tissue.

Malignant tumors grow by penetrating (infiltration) into surrounding tissues and destroying them. They usually do not have a capsule, but in dogs, some, such as malignant tumors of the mammary glands, grow in a capsule. Malignant tumors are characterized by the ability to metastasize, i.e., to spread throughout the body: tumor cells are carried through the blood or more often lymphatic pathways to internal organs, where they give rise to the development of new (secondary) tumor nodes. Histologically, in malignant tumors, the differentiation of cellular elements is reduced and signs of similarity with the original tissue are lost.

With some experience and skills, one can presumably judge whether a tumor is benign or malignant; however, a final diagnosis can only be made on the basis of its microscopic examination. The simplest method is tumor puncture followed by examination of the punctate under a microscope.

Puncture biopsy technique: a sterile needle is inserted into the depth of the tumor, put on a syringe with a capacity of 20 cm 3, in which the piston is pushed in as far as it will go. By repeatedly sharply pulling the piston up, cellular material is drawn into the needle and then, using the piston, it is squeezed out onto a glass slide. Usually this is a mucous liquid, which is smeared on glass with the same needle, dried for 20-30 minutes and stained according to Leishman-Romanovsky. According to the punctate, it is possible to correctly determine the histological type of the tumor under study. If a more accurate diagnosis is required, they resort to incisional biopsy: the skin, subcutaneous tissue, surrounding tissues and capsule are dissected, a piece of the tumor measuring 1´ 1 cm 3 is taken, subjected to special processing adopted in histological laboratories, and the biopsy is studied under a microscope.

In dogs, tumors account for 8-18% of the total number of diseases. They develop in them, as a rule, in the second half of life, on average at 7-9 years and older; in isolated cases, they occur at the age of up to 3-5 years and very rarely - up to 1-2 years.

The tumors are about equally common in both females and males, with the exception of mammary tumors, which affect females and, extremely rarely, males.

There is evidence of a predisposition of certain breeds of dogs to certain types of tumors. So, Scottish Terriers are prone to tumors of the skin, English Cocker Spaniels - of the oral mucosa, Fox Terriers - of the perianal glands. Boxers are especially prone to tumors: they are more likely than dogs of other breeds to have tumor diseases of the blood, skin, etc. Dogs of large breeds (St. Bernards, Newfoundlands, Great Danes, etc.) often have bone tumors.

Tumors can be divided into two groups: external localization and internal organs. Much more is known about the former than about the latter, since they attract the attention of dog owners earlier and force them to go to veterinary clinics.

The principles of clinical classification of tumors have been developed, which allow unifying the assessment of the stage of the disease. The classification is accepted in most foreign veterinary clinics. Its goal is to create a unified system of signs that makes it possible to determine the spread of a tumor both within the affected organ and in areas of regional and distant metastasis.

Under the stage of the tumor process is meant a stage in the development of a tumor disease, expressed as the sum of certain clinical symptoms. The stage of the disease is determined on the basis of such clinical data as the size of the tumor, the degree of damage to the original organ, the degree of transition of the tumor to neighboring organs or surrounding tissues, the presence or absence of metastases. Based on these indicators, stage I means the restriction of tumor growth to the surface tissues of the original organ, small (up to 3 cm) size of the tumor node, and the absence of metastases. Stage II is characterized by a large size of the tumor (up to 5-6 cm), its germination into the deeper tissues of the original organ, but the tumor retains mobility (shifts in relation to the surrounding tissues), there may be single small metastases in the regional lymph nodes. At stage III, the tumor has a significant size (more than 5-6 cm), its mobility is limited due to germination in the surrounding tissues and out of the organ, there are large metastases in regional lymph nodes. Stage IV - this is the spread of the tumor far beyond the affected organ and the presence of distant metastases to the liver, kidneys, lungs, i.e., in fact, the defeat of the entire body.

In 1974, a committee of WHO experts developed a classification of TNM tumors for domestic animals, in particular for dogs. This classification is based on three components:

T - primary tumor (tumores);

N - lymph nodes (noduli);

M - metastases (metastasis).

Each of the elements of this system has several gradations that characterize the degree of spread of a malignant tumor. Depending on the size of the tumor and its germination in the organ or surrounding tissues, T 1, T 2, T 3, T 4 are distinguished. Depending on the defeat of regional lymph nodes, N 0 (no metastases), N 1, N 2, N 3, (respectively, suspicion of metastases, multiple mobile, immobile metastases) are distinguished. The symbol M characterizes the absence (M 0) or the presence of distant hematogenous metastases (M 1). For example, T 3 N 2 M 0 means that there is a tumor larger than 5 cm with germination into the surrounding tissues, multiple metastases to regional lymph nodes, and there is no reliable evidence of the presence of distant metastases.

The TNM classification is, in essence, an improved 4-stage classification, in which stage I corresponds to T 1 N 0 M 0, stage II to T 2 N 1 M 0, stage III to T 1 N 2 M 0, stage IV to T 1 N 3 M 1 . The advantage of the classification is that, in a concise form with the help of symbols, it provides a fairly clear and complete expression of the clinical stage in which the animal with the tumor is at the time of examination. The classification was created in order for veterinarians to apply the same principles and common terminology for assessing the stage of the tumor process.

Tumors of the mammary glands in dogs, they account for more than half of all tumors. They are found, as a rule, in dogs older than 6-7 years and do not occur before the age of 4 years.

The appearance of a breast tumor is preceded by long-term hormonal disorders: an increase in the level of estrogen in the body. It is known that castration of females before the first estrus reduces the likelihood of a mammary tumor by 50 times. An important contributing factor is false pregnancy, which is common in dogs in the second half of life, as well as the lack of mating and natural feeding of puppies. Obviously, the normal functioning of the mammary glands is a factor preventing the development of tumor growth.

In the mammary glands of females, tumors occur with an unequal frequency: in the 1st and 2nd pairs of glands they are rare, in the 3rd pair they are more common, and mainly affect the 4th and 5th pairs. The incidence of tumor growth depends on the functional activity and volume of breast tissue. For example, in the 5th pair of mammary glands, which have the most pronounced functional activity, tumors occur 8-10 times more often than in the 1st pair, in which the volume of glandular tissue and its ability to lactate are very small.

Due to the superficial (subcutaneous) location of tumors in the mammary glands, their intravital diagnosis does not cause difficulty. The formed tumor is a rounded tuberous formation of an elastic or dense consistency. Tumors are, as a rule, single, although it is often necessary to observe multiple neoplasms, and at first one tumor node appears, and only then others. Therefore, speaking of multiple tumors of the mammary glands, one should mean only different stages of the same process, which is of no small importance in determining the size of the surgical intervention.

The onset of tumor growth in the mammary gland is usually associated with estrus or false pregnancy; a small nodule of soft, doughy consistency begins to be felt in the tissue of the gland. Sometimes the nodules are multiple in nature, which on palpation creates a feeling of a "bag of shot". Such changes are not yet a tumor, and they should be qualified as mastopathy, that is, such a pathological condition that is a pre-tumor, but in the future can turn into a tumor. Animals with mastopathy are subject to observation, because after a certain time one appears among the small nodules, which continues to increase in size and acquire a denser consistency. For a long time, the tumor nodule may not change its size or slowly increase, but after the next estrus or false pregnancy, it grows noticeably, becoming dense and bumpy (stage I). If during palpation a slight increase in regional lymph nodes is determined, this means that the process has moved to stage II. A further increase in the tumor is associated with its germination in the surrounding tissues, as a result of which it becomes immobile. The skin covering the tumor often loses hair and becomes tense, hyperemic, hot to the touch. If the tumor is located in the 4-5th pair of mammary glands, its surface, facing the inner surface of the hind limbs, ulcerates as a result of constant injury when the dog moves. However, ulcers, sometimes multiple, can also occur in those parts of the tumor that do not come into contact with the inner surface of the hind limbs. Their appearance can be explained by necrosis and suppuration of individual sections of the tumor. Multiple large metastases in regional lymph nodes are determined (stage III).

At the same time, very often there are tumors that grow in the form of a rounded dense formation, reach sizes of up to 10-15 cm or more, while maintaining mobility in relation to the underlying tissues. Metastases in regional lymph nodes are not detected, although the tumor is malignant, has a complex (mixed) structure with excess mesenchymal tissue up to the formation of a bone component.

A special group is made up of tumors of the mammary glands, growing without a capsule and germinating early aponeurosis, rectus muscles of the abdominal wall and skin. In such cases, an extensive ulcerative surface is found with deep fistulous passages and purulent-necrotic discharge. This form of tumors, which is called armored, is characterized by invasive tumor growth with spread along the lymphatic tract towards regional lymph nodes, which, together with the tumor, form a single immobile complex.

Progressive loss of body weight and appetite, increased thirst, obvious weakness and apathy, cough indicate metastatic lesions of the lungs and other internal organs (stage IV). Metastases in the lungs are clearly visible on chest x-ray, which is performed in a direct or lateral projection. Metastases in other internal organs are not determined by radiography.

Metastasis is a natural stage in the development of a tumor disease if the primary breast tumor has not been surgically removed. Due to the anatomical features of the dog's body, the lymph outflow from five pairs of mammary glands has a different direction: from the 1st, 2nd, 3rd pairs of glands, lymph enters the axillary lymph nodes, where metastases should be looked for when examining an animal with a tumor of this localization. From the 4th and 5th pairs of mammary glands, lymph enters the inguinal lymph nodes, in which the first metastases appear. Due to the fact that the left and right chains of the mammary glands have separate lymph and blood circulation, metastases to the lymph nodes are always found on the side where the tumor is located.

Metastatic spread of a tumor is one of the signs of its malignancy, but the final judgment on the nature of the neoplasm can only be given by a histological study of the removed tumor. The clinical behavior of a breast tumor is largely determined by its histological type, since even malignant tumors have different growth rates and unequal ability to metastasize. Differentiated (mature) tumors have the structure of the so-called papillary or tubular cancers of a simple type, which have a moderate degree of malignancy and a low ability to metastasize.

Breast cancer in dogs often has a very peculiar complex structure, when papillary or tubular structures are combined with neoplastic proliferation of so-called myoepithelial cells; in this case, the tumor of the mammary glands acquires a more benign clinical course, although it is malignant in itself.

Canine mammary tumors are treated surgically. In this case, it is necessary to take into account the age of the animal, the presence of concomitant diseases of the heart, liver, kidneys, as well as the extent of the tumor, i.e., the clinical stage. A prerequisite for surgery for malignant tumors is the observance of the principles of oncological radicalism, which involves the excision of the organ or tissues from which the tumor originates, within a wide range, with the capture of surrounding healthy tissues.

Performing an oncological operation requires knowledge of the features of the spread of the tumor within the affected organ, transition to neighboring organs and tissues, and a clear understanding of the ways of metastasis along the lymphatic tract. High efficiency of long-term results is achieved if the principles of ablastics are observed, which means that the surgeon does not allow the spread of tumor cells during the operation.

The operation to remove a breast tumor is performed in several stages:

1. When the tumor is localized in the 5th-4th pair, at least 3 cm away from the edge of the tumor, the skin is dissected with two bordering semi-oval incisions and separated to the side.

2. The anatomical boundaries of the tumor are exposed, the fatty tissue is dissected to the aponeurosis.

3. Vessels supplying the tumor are ligated with catgut in the cranial and caudal parts of the surgical wound, departing from the visible boundaries of the tumor by 3-5 cm.

4. Bluntly, a block of tissues is dissected together with fatty tissue and a tumor from the aponeurosis, exposing the feeding vascular pedicle. Allocate superficial inguinal lymph nodes.

5. The vascular pedicle is carefully stitched with silk and crossed. The surgical wound is sutured in layers and tightly, and rubber drainage is left in its caudal part for one day.

6. When removing a tumor located in the first three pairs of mammary glands, the fringing incision of the skin and fatty tissue is continued to the armpit and the tumor and lymph nodes are isolated in a single block, followed by layer-by-layer suturing of tissues and skin. Drainage in this case is inserted into the cranial end of the wound.

A contraindication to surgical treatment is the generalization of the tumor process, i.e., dissemination of the tumor and the appearance of distant metastases.

Surgical treatment is most effective when the following conditions are present:

1. The tumor does not spread to the surrounding tissues (stages I-II). With the spread of the tumor to the surrounding tissues and the development of metastases in the regional lymph nodes (stage III), the surgical method is also applicable, but the long-term results in such cases are worse.

2. The boundaries of the tumor and its visible delimitation from the surrounding tissues are clear. Their absence reduces the possibility of radical removal of the tumor.

3. The rate of tumor growth is a factor that determines the effectiveness of surgical intervention in terms of prognosis. With a long development of the process, it is possible that the malignant tumor is mature and the favorable outcome in this case is much higher.

When it is known that radical removal of the tumor is impossible, sometimes they resort to the so-called palliative surgery: a large disintegrating or bleeding tumor is removed in order to subsequently act on the remainder of the tumor or its metastases with radiation or antitumor drugs. However, this is possible only in specialized institutions.

Removal of a breast tumor in I-II clinical stages is not difficult. The outcome and prognosis are favorable. The volume of the operation at stage III is much larger; a wide excision of the tumor, surrounding tissues, including the aponeurosis, sometimes part of the rectus muscles of the abdominal wall, and a package of lymph nodes is required. The outcome and prognosis are not always favorable, relapses and the appearance of distant metastases are possible. Nevertheless, the life expectancy of dogs operated on for simple tubular or papillary breast cancer is 12-16 months on average, and 16-36 months for complex type tubular or papillary breast cancer.

If the animal has several tumors of the mammary glands, then first the tumor node is removed, which has the largest size and represents the main danger to the animal. In the future, after the removal of the sutures and after the animal has fully recovered from the surgery, the issue of the need to remove other tumors of the mammary glands is decided.

Tumors of the skin and subcutaneous tissue can occur in any part of the body; they are rounded formations that rise above the surface of the skin. Often there is a need to differentiate them from formations of a non-tumor nature: cysts (dermoid), which grow slowly and contain a thick liquid inside; retention cysts that develop as a result of blockage of the output ducts of the skin glands, such as sebaceous.

Papillomatosis of the skin and oral mucosa is a tumor-like disease and is a multiple rash in the form of small formations on thin legs. For the treatment of papillomatosis, intravenous administration of 0.5% novocaine can be recommended.

A benign tumor of the skin and subcutaneous tissue has a rounded shape and elastic consistency, the coat over the tumor is not changed.

A malignant tumor of the skin is most often a flattened formation that grows mainly in breadth and retains mobility in relation to the underlying tissues for a long time. There is no coat over the tumor, the surface is bumpy, often bleeds, covered with fibrinous-necrotic overlays. Metastases to regional lymph nodes occur relatively late. This type of tumor is most often a squamous cell carcinoma.

Treatment of tumors of the skin and subcutaneous tissue is their surgical removal.

Malignant tumors of the skin require a wide excision with the capture of surrounding tissues and regional lymph nodes, if they are enlarged due to metastatic lesions. If the tumor is located on the extremities, where the supply of skin is limited, then after excision of the tumor, a defect occurs that requires plastic replacement. To do this, on any area of ​​the skin where there is a sufficient supply of it, a section corresponding to the size of the defect is outlined and cut out, and it is sewn, combining the edges of the flap and the skin defect. In more complex cases, they resort to the formation of a skin stem according to Filatov.

Pigment-containing tumors - melanomas - occur in the skin or mucous membrane of the oral cavity in the form of a rounded dark-colored node. When localized in the skin, the tumor grows slowly, retains mobility and has a relatively benign clinical course, metastasizes late. Surgical removal of the tumor is not difficult. When localized on the mucous membrane of the mouth, melanoma quickly grows into the surrounding tissues, becomes immobile and early metastasizes to the cervical lymph nodes. The tumor is prone to bleeding due to constant trauma to its teeth and food. Surgical removal of such a tumor is not always possible even for an experienced specialist.

Mast cell tumors (mastocytomas), which are solitary rounded intradermal formations, constitute a special group. The coat over the tumor is absent. It occurs more often on the lateral surfaces of the trunk and limbs and occurs, as a rule, in boxers. During surgical removal, it persistently recurs, and new nodes appear near the removed one. The tumor is resistant to both drug treatment and radiation.

Tumors of the perianal (near-anal) glands quite common in dogs, and it is characteristic that they occur only in males. Diagnosis of neoplasms is not difficult due to their typical location around or near the anus. Tumors are usually multiple. There is no coat over them, the skin is tense, often there are deep fistulous passages with purulent-necrotic discharge. The occurrence of tumors is associated with an increase in the body's level of male sex hormones (androgens), produced by special cells in the testes. A connection has been established between tumors of the perianal glands and testicular tumors (leidigoma) or with hyperplasia of leydig cells that produce androgens.

Surgical removal of perianal gland adenomas is ineffective. Tumors stubbornly recur after removal, or new nodes appear in the perianal region. Due to the fact that these tumors are of dyshormonal origin, castration of the animal may be recommended, followed by long-term administration of female sex hormones (sinestrol at a dose of 1 mg per 5 kg of animal weight daily for 3-4 months). The ulcerative surface epithelizes, tumor nodes decrease and sometimes completely disappear, however, the cessation of estrogen administration can lead to a re-growth of perianal tumors.

Lymphosarcoma(lymph node sarcoma) refers to a group of diseases with a general (systemic) lesion of the lymphoid tissue. The disease occurs in dogs aged 4-7 years and usually begins with a unilateral enlargement of the submandibular or other superficial lymph node, which is painless and retains mobility (stage I). In this period, the general condition of the animal is good, the appetite is preserved, no changes are noted in the peripheral blood. In the case of an increase in the submandibular lymph node, it is necessary to exclude the inflammatory process in the oral cavity (tonsillitis, dental disease), in which the enlarged lymph node is painful on palpation. The progression of the disease is expressed in an increase in the group of lymph nodes, which are a single immovable conglomerate with swelling of the surrounding tissues (stage II). In the blood, no changes are also observed. Stage III is characterized by an increase in all superficial lymph nodes (cervical, axillary, inguinal, popliteal), which often leads to thickening and swelling of the limbs due to impaired lymph outflow (lymphostasis). Further development of the disease (stage IV) is accompanied by damage to the bone marrow and an increase in the liver and spleen, accumulation of fluid in the abdominal cavity (ascites) is possible. In the peripheral blood, immature lymphoid cellular elements (blast forms) are observed. The general condition of the animal is characterized by lethargy, lethargy, he has no appetite, frequent, liquid stools, thirst is noted, copious separation of viscous saliva, the dog sharply loses body weight.

The diagnosis of lymphosarcoma is made on the basis of a puncture of the lymph node, followed by a microscopic examination of the punctate, in which immature (blast) forms of lymphoid cellular elements are found. Lymphosarcoma is sensitive to modern antitumor drug therapy, which can cause a decrease in lymph nodes to normal sizes and a stable complete remission lasting up to 3-4 months. Surgical removal of an enlarged lymph node is impractical, since this leads to rapid growth of the tumor at the site of surgery and in other lymph nodes, i.e., it contributes to the rapid generalization of the process.

Sarcoma of the mesenteric lymph nodes (intestinal form of lymphosarcoma) is a rather rare and difficult to recognize disease, since it does not have clear symptoms. Clinically characterized by alternating constipation and diarrhea, not amenable to conventional treatment, weakness, weight loss. On palpation, a tumor formation is determined in the abdominal cavity, which is not immediately associated with enlarged mesenteric lymph nodes. For a more accurate diagnosis, a trial laparotomy may be recommended, in which a conglomerate of enlarged mesenteric lymph nodes is detected. Treatment is only medicinal in specialized institutions.

lymphocytic leukemia is a tumor systemic disease of the hematopoietic tissue; characterized by proliferation in the bone marrow, spleen, liver and other internal organs of immature (blast) cells of the lymphoid series. It occurs in relatively young dogs (average age 3-5 years). It begins with inexplicable weakness, loose stools, refusal to feed. In the future, pallor of the mucous membranes, shortness of breath develop, a rise in body temperature to 40-41 ° C is possible. Superficial lymph nodes are not enlarged or enlarged very slightly. In lymphocytic leukemia, the proliferation of blast cells in the bone marrow and their release into the peripheral blood contribute to the suppression of hematopoiesis, which leads primarily to deep anemia (a decrease in the number of erythrocytes to 1.5 million, hemoglobin to 70 g/l) and leukocytosis (40-50 thousand per liter). ), and not only a shift of the blood formula to the left is characteristic, but also an absolute increase in the number of lymphocytes. The number of blast cells in the bone marrow and peripheral blood reaches 50% or more.

With the help of modern anticancer drugs, it is possible to induce a short remission and a general improvement in the condition of the animal, but in general the prognosis is unfavorable: depending on the stage of the disease, dogs live no more than 4-6 months, subject to intensive antitumor treatment.

Thus, the state of hematopoiesis in dogs with lymphosarcoma and lymphocytic leukemia has characteristic features that should be taken into account in differential diagnosis. So, in dogs with lymphosarcoma without bone marrow damage, hematological parameters practically do not differ from the norm. The progression (generalization) of lymphosarcoma is accompanied by the appearance of blast cells in the bone marrow and peripheral blood. In lymphocytic leukemia, blast cells are found in the bone marrow and peripheral blood from the very beginning of the disease, and their proliferation in the bone marrow leads to suppression of hematopoiesis.

Transmissible sarcoma better known as venereal sarcoma. It occurs in both males and females aged 2-4 years, more often in stray dogs or dogs leading a relatively "free" lifestyle (huskies, hounds). The tumor is located on the mucous membrane of the genital organs and is transmitted from individual to individual only through sexual contact, differing in exceptionally high contagiousness. The tumor is transmitted by living cells, which break away from the tumor during sexual intercourse and are implanted on the mucous membrane of the partner's genital organs. The tumor does not metastasize, and even in advanced cases, regional (inguinal) lymph nodes are free from metastases. It is often possible to see the spread of tumors along the mucous membranes of the oral cavity, nose and eyes, which is not metastasis, but mechanical implantation of living tumor cells, which occurs, for example, when a dog licks a tumor.

The first clinical sign of a tumor is the release of drops of blood from the external genital organs, upon examination of which a loose bleeding formation is found on a wide base, resembling a cauliflower.

Transmissible sarcoma occupies a special position among canine tumors because it is clearly contagious, i.e., it is not a tumor in the strict sense of the word. At the same time, according to the microscopic structure, it has all the signs of a malignant tumor, and it should be attributed to the group of alveolar-type sarcomas.

Transmissible genital sarcoma does not pose an immediate danger to the life of the animal, however, treatment should begin as soon as the diagnosis is established. Surgical removal of the tumor is possible, but it persistently recurs unless radical excision is made, and this is associated, especially in males, with the need for careful hemostasis and suturing of a large defect in the cavernous bodies and the mucous membrane of the penis. Good results are obtained by local irradiation of the tumor with gamma or x-rays. The tumor is also sensitive to modern antitumor cytostatics (cyclophosphamide, vincristine).

Tumor of the vaginal wall(leiomyoma) occurs in older dogs (mean age 10-11 years), has a benign character. In practical terms, it becomes necessary to differentiate a tumor from a transmissible sarcoma. The tumor of the vaginal wall has a dense texture, does not bleed, the mucous membrane covering it is dry, the submucosal blood vessels are full-blooded.

Tumor growth in the direction of the tissues surrounding the vagina is possible. In this case, it can be palpated in the perineum in the form of a formation located in the depths of the small pelvis, which can lead to impaired urination and defecation.

Surgical removal of superficial tumors of the vaginal wall is not difficult. If the tumor is located in the depths of the small pelvis, then access through the perineum is recommended, but in this case, the removal of the tumor is associated with the risk of damage to the urethra, into which a catheter should be inserted before the operation.

testicular tumors are easily detected by external examination and palpation of the scrotum, although they do not immediately attract the attention of dog owners. Usually the tumor develops in one testis, but in 10-15% of cases it occurs in both. It is characteristic that when a tumor occurs in one testis, the second one atrophies. About a third of all tumors develop in the undescended testes and in young dogs (mean age 6-7 years). In the descended testis, the tumor occurs at an older age (9-10 years). An undescended testicle with a tumor is located either in the inguinal canal, which is easy to detect on palpation, or in the abdominal cavity, where tumor detection is associated with certain difficulties.

According to the histological structure, testicular tumors can be divided into three types: seminomas (tumors from the seed epithelium), tumors from sertoli cells (sertoliomas) and tumors from leydig cells. Clinically, all these tumors behave differently. So, sertoliomas produce female sex hormones (estrogens), a long-term increase in the level of which leads to suppression of secondary sexual characteristics and a change in the behavior of males. Dogs with sertolioma show symmetrical alopecia in the chest, abdomen, and lateral surfaces of the hind limbs. The coat becomes dry and brittle, the skin thickens, especially the scrotum, the mammary glands increase, the prepuce decreases, and sexual activity decreases. However, it would be wrong to say that the described picture is typical for all sertoliomas. A certain part of the tumors does not have such manifestations, but it has been noted that the effect of estrogenemia of sertoliomas is much more pronounced when a tumor occurs in the testis that has not descended from the abdominal cavity. After removal of the tumor, the feminization phenomena disappear quite quickly: already 4-6 days after the operation, the level of estrogen in the urine decreases to normal. Sertoliomas metastasize late.

Tumors from Leydig cells (leydigomas) occur, as a rule, in a descended testicle and produce male sex hormones (androgens), a long-term elevated level of which in the body creates a constant background that contributes to the occurrence of tumors of the perianal glands. In practical work, it is quite common to see both tumors of the testicles (leidigoma) and tumors of the perianal glands at the same time. Leydigomas are benign and do not metastasize.

Seminomas have no hormonal activity, usually develop in the descended testes in older dogs (mean age 10-11 years); rarely metastasize, mostly to regional (inguinal) lymph nodes.

Tumors of the testes, regardless of their histological structure, have a relatively slow growth, do not germinate the membranes of the testis, and their surgical removal is not difficult, especially if the testis affected by the tumor is located in the scrotum or inguinal canal. The most crucial moment in the operation is the ligation and crossing of the feeding artery. Removal of a tumor of the testis located in the abdominal cavity is performed in accordance with the general rules for abdominal operations.

Tumors of the prostate- very rare, although non-tumor enlargement of the prostate (hypertrophy) is common in dogs older than 10 years. The probability of transition of hypertrophy to cancer is extremely low, no more than 1%. Prostatic hypertrophy for a long time does not have any clinical manifestations, and only in cases where its increase leads to compression of the rectum, characteristic symptoms begin to appear. Usually, owners note in dogs a gradual lengthening of the act of defecation, associated with the impossibility of complete emptying of the intestines. Prolonged tenesmus leads to the development of perineal hernia and even prolapse of the rectum.

Prostate hypertrophy occurs in conditions of long-term hormonal disorders and is possibly associated with an increased level of male sex hormones (androgens) in the body. It is also known that hypertrophy occurs, as a rule, in males who did not have matings.

Distinguishing prostatic hypertrophy from cancer using clinical techniques is almost impossible. Prostate cancer in dogs metastasizes late, the tendency of the tumor to grow locally with the destruction of surrounding tissues and germination into the urethra or bladder prevails. In these cases, the appearance of blood in the urine is characteristic.

Treatment of hypertrophy and prostate cancer is mainly symptomatic. Sometimes the introduction of large doses of sinestrol or castration helps.

bone tumors occur in dogs as young as 6-7 years of age, although they are thought to occur earlier. Slowly developing, sometimes for many years, they do not show themselves. The first clinical signs of a tumor, if it develops in the bones of a limb, are lameness and a clear unwillingness of the dog to get up from his seat, especially in the morning, about which dog owners turn to a veterinarian. During this period, when palpating the limb on which the dog is lame, the tumor may not be detected or a small, dense, moderately painful thickening near one of the joints is determined. Unfortunately, it happens that lameness is associated with an alleged trauma in the past, and the dog is prescribed compresses or other warming therapy, which in this case is absolutely contraindicated.

Bone tumors are somewhat more common in males than in females, and almost exclusively in dogs of large breeds, such as St. Bernards, Great Danes, Newfoundlands, etc., i.e., in those dogs in which, during the period of intensive bone growth, the length a large physical load on the limbs, especially on the chest.

About 80% of tumors are localized in long tubular bones, and in the thoracic limbs 3 times more often than in the pelvic. Tumors can also occur in the ribs, vertebrae, flat bones of the skull, iliac bones of the pelvis, but much less frequently than in the extremities. Characteristically, in the bones of the extremities, tumors are located mainly in areas corresponding to growth zones, namely, in the metaphyses. Most often, the tumor in the humerus is localized in the proximal metaphysis, and in the radius, femur, tibia - in the distal metaphysis.

Bone tumors can be recognized using histological (biopsy) and X-ray methods of examination. The histological structure of the tumors is quite diverse. Benign tumors (osteomas) are usually localized in the ribs or bones of the skull. The most common (up to 85%) of malignant tumors is osteogenic sarcoma, i.e., a tumor originating from bone tissue. Chondrosarcoma, fibrosarcoma, osteoblastoclastoma are much less common.

Clinically, all of the listed bone tumors do not have specific features, and it is not possible to distinguish one from the other using conventional techniques (palpation). X-rays reveal characteristic features that help establish the correct diagnosis.

So, with osteogenic sarcoma, the site of bone destruction with increased bone formation (osteosclerotic type) or bone resorption (osteolytic type) is usually clearly visible. A characteristic feature is peculiar osteophytes, or outgrowths, which have the shape of a "peak", located at an angle to the long axis of the bone and representing a reaction of the periosteum in the form of its detachment. Another characteristic sign of osteogenic sarcoma is the formation of thin calcifications with a direction perpendicular to the bone, forming a “fan” pattern. The spread of osteogenic sarcoma into the surrounding tissues leads to the formation of an extraosseous component, in which fields of ossification develop in the form of flaky or cloud-like seals, visible on radiography.

Fibrosarcoma and osteoblastoclastoma are difficult to distinguish on x-ray from osteogenic sarcoma. Histological confirmation of the diagnosis is required. X-ray features of bone chondrosarcoma are the presence of large foci of osteodestruction and the absence of osteophytes, "visor" and ossification of the extraosseous component.

Establishing a diagnosis only by radiographs is impossible, even if the doctor has some experience. The leading role in this case belongs to the histological study of the material obtained by incisional biopsy, which, by the way, does not have any negative consequences for the sick animal, as some believe.

The final clarification of the diagnosis is based, therefore, on the totality of clinical, radiological and histological data. The exact establishment of the nature and nature of the bone tumor is important in the sense that it determines the prognosis.

Bone tumors grow relatively slowly, but nevertheless their development proceeds through certain stages and corresponds to certain clinical stages. If the tumor is palpated as a small, moderately painful lump, which is mainly a reaction of the periosteum, and the radiograph shows a limited bone compaction that does not extend beyond the cortical layer, then this stage can be assessed as I. A clearly palpable painful mass that has a pronounced reaction on the radiograph periosteum (osteophytes, "visor"), corresponds to stage II. A further increase in the tumor, swelling and tension of the skin, the appearance of weeping ulcerative surfaces on it, an increase in the regional lymph node (metastasis) means the transition of the process to stage III. In case of animal weakness, refusal of food, coughing, sudden loss of body weight, it is necessary to perform a chest x-ray, and if multiple metastases to the lungs are visible, then this corresponds to stage IV.

Treatment of bone tumors is undoubtedly the most difficult problem of modern oncology. In medical oncology, schemes of drug and radiation exposure have been developed that can significantly suppress tumor growth. These regimens can be used in the treatment of bone tumors in dogs, but only in specialized institutions. However, in general, the prognosis of bone tumors in dogs remains unfavorable, especially in the case of osteosarcoma, with which dogs live no more than 2-3 months (in the absence of specific antitumor treatment). The life expectancy of dogs with chondrosarcoma, especially with fibrosarcoma and osteoblastoclastoma, is up to 5-6 months.

Speaking of bone tumors in dogs, one cannot fail to mention secondary, i.e., metastatic, bone tumors, which are most often metastases of breast cancer. These tumors are usually localized in the area of ​​the diaphysis of one of the long bones, are painful on palpation, cause lameness in dogs, and radiologically are characterized by a focus of osteolytic destruction in the absence of a periosteal reaction. A decisive role in the differential diagnosis is played by an indication that there was a malignant tumor of the mammary gland removed surgically in the anamnesis.

Thyroid tumors- the disease in dogs is quite rare, occurs at the age of 9-10 years. Tumors can be benign (adenomas) or malignant (cancers), the latter growing much faster. Located in the middle third of the lateral surface of the neck and protruding outwards, thyroid tumors are immobile in relation to the surrounding tissues from the very beginning. They show an obvious connection with the trachea and, sometimes reaching considerable sizes, lead to its deformation and difficulty in breathing. The tumor usually affects one lobe of the thyroid gland.

The tumor is subject to surgical removal, and this operation is one of the most difficult. However, before deciding on an operation, it is necessary to make sure that there is no metastatic lesion of the deep cervical lymph nodes. An important point is also the careful selection of the neurovascular bundle passing in the area of ​​the operation. Due to the fact that the second lobe of the thyroid gland, not affected by the tumor, remains in the body, special therapy with thyroid-stimulating hormones in the postoperative period is not required.

Tumors of the tonsils occur in dogs of different ages and are easily detected by a careful examination of the oral cavity. The tumor usually affects one tonsil and is a soft friable formation with a bumpy, sometimes bleeding surface. According to the histological structure, it has the character of squamous cell carcinoma or, less commonly, lymphoepithelioma. Early metastasis of tonsil cancer to the deep cervical lymph nodes and lungs is characteristic. Treatment is only surgical, and radical removal of the tumor node with good hemostasis is necessary. In the presence of metastases, there are serious doubts about the appropriateness of a surgical operation.

Tumors of internal organs in dogs are difficult to diagnose due to the absence of any specific signs and clinical manifestations that could indicate a tumor lesion of a particular organ. Even when the tumor reaches a significant size and there are changes in the activity of the organism, then even then the symptoms are very general, which does not allow one to suspect a tumor process. Such common phenomena observed, for example, in tumors of the liver and spleen, include ascites, pallor of the mucous membranes, anemia, weakness, refusal of food, thirst. Clinically, ovarian tumors can manifest themselves in violation of estrus, prolongation of the estrus phase with constant spotting. With tumors of the bladder and kidneys, hematuria, dysuric phenomena, weakness, and adynamia may be noted. With tumors of the stomach, which are extremely rare in dogs, phenomena develop that are primarily associated with obstruction (vomiting of food eaten, exhaustion, weakness).

With sufficient experience, the veterinarian can determine by palpation a certain mass in the abdominal cavity and suggest which organ the tumor is likely to come from, but there is usually no complete certainty. X-ray examination of animals in which a tumor of any internal organ is suspected gives very scarce data even with the introduction of air into the abdominal cavity. The use of radiopaque agents for the diagnosis of tumors is a complex procedure that requires special skills and good equipment that allows serial images to be taken.

In all cases where there is a suspicion of a tumor in the abdominal cavity, it is necessary to resort to a diagnostic laparotomy, if the general condition of the animal allows this surgical intervention.

It should be emphasized that the tactics of surgical treatment and the scope of surgical intervention are determined primarily by the histological structure of the tumor and the clinical stage of the disease.

It has already been said that there are factors that contribute to the emergence and growth of tumors. Such facts as the absence of mating and frequent false pregnancies, cryptorchidism and symmetrical alopecia or the presence of a tumor of the perianal glands, lameness in large dogs, prolonged tenesmus and perineal hernia in males, and other symptoms - all this should attract the special attention of veterinary specialists and form in them a feeling of oncological alertness. However, oncological alertness should not turn into overdiagnosis, that is, into a tendency to see a tumor everywhere, especially where it is not accessible to external examination, for example, in the abdominal cavity. In all cases, the doctor must be confident in his diagnosis or have sufficient grounds to suspect a tumor.

Many tumors in dogs respond well to surgical treatment if the diagnosis is correctly made, and the operation is performed at an early stage (without tumor invasion into surrounding tissues and metastatic spread) and performed according to the rules of ablastic surgery. The treatment of lymphosarcoma and osteogenic sarcoma is still ineffective, although with the help of modern drugs and methods of radiation and combined exposure, in some cases it is possible to achieve a significant extension of the life of sick animals.

Oncological diseases in dogs are practically no different from oncological diseases in humans. There are many theories of the origin of tumors. Some scientists believe that the cause of oncology in dogs is a virus (herpes virus, papillomavirus), others are the result of exposure to the body of chemical and physical carcinogenic factors (carcinogenic substances, radioactive radiation). At the same time, there are theories explaining the cause of oncological diseases in dogs by hormonal disruptions in the body or a violation of tissue development in the process of ontogenesis. In recent years, the most likely cause of neoplasms in dogs is considered to be the result of cell mutations that occur at the genetic level.

A neoplasm is a group of cells in a newly formed tissue in which the processes of growth, differentiation and reproduction of cells are disrupted. Cancer tissue is characterized by tissue (cellular) atypia, progressive growth and relative autonomy from other tissues.

Neoplasms in a dog are characterized by the appearance of metastases with blood and lymph flow in various organs.

Types of neoplasms in dogs.

All neoplasms are usually divided into benign and malignant. For benign neoplasms, it is characteristic that they grow slowly, often have their own capsule or membrane, do not grow into the tissues surrounding the tumor, do not metastasize, and after their removal there are practically no relapses.

Malignant neoplasms are characterized by rapid growth, germination into surrounding tissues, and give metastases. After their removal, they often reappear. On histological examination, malignant cells are poorly differentiated, so it is difficult to determine from which tissue they originate. With a malignant neoplasm in the body of a sick dog, a deep metabolic disorder occurs, symptoms appear from the organs affected by the tumor.

Depending on the type of tissue affected by a malignant tumor, veterinary specialists distinguish the following groups of malignant tumors:

• carcinoma is a tumor arising from epithelial cells.
• myosarcoma is a tumor of muscle cells.
• melanoma is a tumor of pigment cells.
• sarcoma is a tumor of connective tissue cells.
• osteosarcoma is a tumor of bone cells.
• lymphoma is a tumor of the cells of the lymphatic tissue.
• Glioma is a tumor of glial cells.
• teratoma - a tumor formed from germ cells.

Additionally, other types of tumors occur in dogs.

clinical picture. Veterinarians divide the available types of cancer in dogs into:

Canine mammary tumor

Breast tumors make up 50% of all neoplasms in bitches. The average age of affected bitches is 9 years. Histologically, tumors are divided into epithelial (benign - adenomas and malignant - adenocarcinomas), mesenchymal (benign - fibromas, chondromas, osteomas, myoepitheliomas, malignant - fibrosarcomas, chondrosarcomas, etc.) Veterinary specialists of the clinic determine this type of tumor during a clinical examination of a sick dog , during palpation of the mammary gland, the veterinarian palpates a tumor of various sizes. Which can be either single or multiple. Moreover, their diameter varies from 0.5 cm to 10 cm. On palpation, the veterinarian defines them as painless enlargements, often of a nodular consistency with a smooth or irregularly bumpy surface. Benign tumors are considered to be small, grow slowly, have not grown together with the skin covering them and are mobile relative to the pectoral and abdominal muscles. With a malignant course, veterinary specialists note the rapid growth of the tumor, it is fused with the abdominal wall, skin ulceration appears over the tumor. The malignancy of a breast tumor is indicated by the presence of metastases in regional lymph nodes or individual organs.

Treatment. Breast tumors that are less than 1 cm in diameter do not require any treatment at first. Owners of such dogs should regularly check them at the veterinary clinic for a possible increase in the size of the tumor. Larger and rapidly growing breast tumors need to be surgically removed as a matter of urgency. If a malignant tumor is suspected (ulcerated surface, infiltrative growth, the tumor does not move relative to the abdominal wall, then the veterinarian during the operation must remove the maximum possible amount of tissue. If the dog has enlarged inguinal lymph nodes, they are also removed. In addition If we are dealing with tumor lesions of several pairs of nipples, then it becomes necessary to excise the entire breast line.During the operation, it must be taken into account that large blood vessels often pass in the upper and lower parts of the mammary gland complexes, during the operation it is necessary to resort to their ligation along separately.In order to prevent surgical bleeding, they often resort to intravenous drip of Ringer's lactate solution before surgery.If a sufficiently large cavity remains as a result of the operation, and also if the bleeding cannot be completely stopped, leave a cigarette drain. we eat with the help of absorbable suture material with a purse-string suture we sew the subcutaneous layer. The skin is sutured with separate knotted sutures.

Tumor of the vagina

Tumors of the vagina. They are found predominantly in older bitches. While tumors are mostly benign (leiomyomas, fibromas, lipomas), malignant cancerous tumors or fibrosarcomas are rare in dogs. In this case, benign tumors of the vagina can be either single or multiple and often have the form of polyps or cover large areas of the walls of the vagina.

Clinic. With this type of tumor in a sick dog, bloody or purulent discharge appears from the vagina. When the tumor is located in the back of the vagina, we note an increase in volume in the perineum. Sometimes there is difficulty in the dog the act of urination or defecation.

Treatment. Tumors of the vagina are removed by surgery.

Tumor of the uterus

Tumors of the uterus. This type of tumor in dogs is rarely recorded and they occur mainly in smooth muscles and are usually benign (leiomyomas). Violations occur in a dog when, due to an increase in the size of the uterus, compression of other abdominal organs occurs or when adhesions and adhesions form at the site of mechanical irritation in the abdominal cavity. The owner may be alerted by the appearance in the dog of frequent unnatural bowel movements from the external genitalia, miscarriage or the absence of a fetus in a previously pregnant dog. Provoking uterine cancer in dogs is usually the use of hormonal drugs by owners that affect estrus. Tumors of the uterus in dogs are most often diagnosed in the last stages of their development. The dog from severe pain often begins to whine, there are disturbances in the activity of the intestines, drowsiness, apathy, tries to move as little as possible.

Treatment is operative.

Testicular tumor

Testicular tumors. Found in older males. The most common types of tumors are leydig cell tumors, ledigomas, seminoma tumors, Sertoli tumors, sertoliomas.

Clinic. The testicles are enlarged on clinical examination, palpation is nodular and hard.

Bone tumors. Bone tumors in dogs in most cases are malignant and tend to metastasize. Veterinarians most often have to deal with osteosarcomas, which are predominantly found in dogs of large breeds (greatest dogs, shepherd dogs, boxers, etc.). They are found mainly in the area of ​​the metaphysis, sometimes at the site of healing fractures.

Clinic. The disease in a dog is accompanied by lameness, the dog carefully steps while walking, quickly gets tired. On palpation at the site of the tumor, the dog reacts painfully.

Treatment. Conservative treatment with cytostatic agents is ineffective. Surgical treatment consists of immediate amputation and further chemotherapy.

skin tumor

Skin tumors. It is quite rare in dogs. It is quite difficult for dog owners to notice this type of tumor, since the dog is covered with a layer of wool. Usually, this type of tumor can be detected during water procedures, when dark spots resembling moles are found on the skin. The color of these moles can vary from pinkish to dark gray. Sertolioma is a skin tumor that arises from Sertoli cells. Boxers are predisposed to this tumor.

Mast cell tumors (mastocytoma, with multiple tumors - mastocytosis) are widespread skin neoplasms. The tumor consists of transformed mast cells. It should be noted that this is one of the rarest tumors in humans, so rare that it is not presented in every manual for diagnosing skin tumors in humans.

SLIDE 1. Mastocytoma in dogs (mast cell tumor)

Mast cell tumors (mastocytoma, with multiple tumors - mastocytosis) are widespread skin neoplasms.
The tumor consists of transformed mast cells.

SLIDE 2. Mast cells. schematic drawing

Mast cells (mastocytes, mastocytes) are highly specialized immune cells of the connective tissue of vertebrates, analogues of blood basophils. Involved in adaptive immunity. Mast cells are scattered throughout the connective tissue of the body, especially under the skin, around the lymph nodes and blood vessels; found in the spleen and bone marrow. Like basophils, the surface of mast cells has receptors for IgE immunoglobulins.

Mast cells contain a large number of cytoplasmic granules stained with cationic dyes. The granules include proteoglycans (heparin), histamine, interleukins and neutral proteases. When activated (for example, during an allergic reaction), mast cells release the contents of the granules into the surrounding tissue. Histamine-releasing mast cell degranulation is an IgE-mediated reaction induced by certain antigens, an immediate-type hypersensitivity reaction.

Some antigens can cause mass degranulation of mast cells, causing urticaria and more serious reactions up to allergic shock. In addition, mast cells also respond to any tissue injury, in which case degranulation is triggered by other cytokine mechanisms. In addition to histamine, which dilates blood vessels, mast cell granules contain heparin, a platelet activating factor, and other substances.

SLIDE 3. Spread of mastocytoma

It should be noted that this is one of the rarest tumors in humans, so rare that it is not presented in every manual for diagnosing skin tumors in humans.
It is also a fairly rare tumor in cattle. In cows, mastocytoma is malignant and multiple. In this case, the tumor can be either a metastasis from the internal organs or a primary skin tumor. It is found in the spleen, muscles, gastrointestinal tract, and uterus.

SLIDE 4. Spread of mastocytoma

In horses, this is a fairly rare tumor. They usually appear as soft tissue tumors on the scalp, neck, trunk, and legs. Pigs and mastocytoma also have a rare tumor. But if in cows these are multiple malignant tumors, then in pigs they are, as a rule, benign single tumors.

SLIDE 5. Mastocytoma in dogs and cats

Dogs and cats are leaders in the animal kingdom in the occurrence of tumors from mast cells.

So, in dogs and according to A.S. White (2003) the incidence of mastocytes is 21% of all skin tumors in dogs. The terms mast cell tumor and mastocytoma are used interchangeably.
As a rule, tumors in dogs are of a single nature, less often occurs in the form of multiple nodules. Sometimes mastocytomas can partially reduce, decrease in size and turn pale, but then, as a rule, increase again.

Almost always, mastocytomas are subject to ulceration, they cause itching, and dogs can part of them and even chew them. Classification of mastocytes in dogs is still an unexplored area, it is not possible to identify the morphological features of the tumor, which make it possible to speak unambiguously about the prognosis of the disease.

Gastrointestinal and splenic lesions are more common in cats than in dogs. Up to 50 percent of all cases of mast cell in cats are associated with damage to the spleen or intestines. Most often they are found in the muscular layer of the intestinal wall. Mastocytoma is the third most common intestinal tumor in cats after lymphoma and adenocarcinoma. In addition, in cats, a mastocytoma has been identified clinically similar to histioma in dogs, in the form of a small red nodule, which, after ulceration, may resolve itself.

SLIDE 6. Predisposition to mastocytoma
depending on the breed of dog

Among dogs, there is a pronounced breed predisposition, so in descending order to mastocytoma are predisposed: Boxer, Staffordshire Terrier, English Bulldog, French Bulldog, Basset Hound, Boston Terrier, Beagle, Sharpei.

SLIDE 7. Mastocytoma - mimic

Canine mastocytomas are known among veterinary oncologists as great mimics because their appearance is so varied that they can mimic almost any skin disease. Mastocytomas can range in appearance from a simple wart or mild subcutaneous lipoma to moist dermatitis, with the pet owner suspecting a dangerous tumor in the very last case. Therefore, any skin lesions should be subjected to cytological examination.

However, most cases of mast cellomas are diagnosed as small nodules on the skin that are prone to erosion. As a rule, the hair at the site of the lesion falls out, and the formations themselves itch, forcing the dog to scratch the affected area. Most tumors are single, but in about six percent of cases, they are multiple, which is especially common in Boxer and Pug dogs.

Any, even minor manipulation of the tumor can lead to its redness and swelling, due to degranulation of the mast cells that make up the tumor. In rare cases, a mastocytoma is a very malignant tumor, in which case signs such as loss of appetite, vomiting, diarrhea, and anemia develop. The presence of these features usually indicates mastocytosis, in which malignant mast cells spread throughout the body.

SLIDE 8. Classification of mastocytes according to the degree of differentiation

DIAGNOSTICS OF MASTOCYTOMS IN DOGS
(Mast Cell Tumors in Dogs)

There are practically no specific clinical manifestations characterizing mastacytoma, but the tumor is easily diagnosed using a fine-needle aspiration biopsy. Tumor puncture with a thin needle is practically painless for a dog, the resulting material is placed on a glass slide, smears are prepared, stained according to Romanovsky-Giemsa and subjected to examination. Mastocytoma cells are large, round cells that contain a large number of dark-colored granules. When a large amount of granules is released and their systemic action releases, vomiting, stomach ulcers, shock, and even death of the animal can develop.

Mastocytoma cells behave very unpredictably, it should be noted that even today there are no absolute criteria that can convincingly distinguish a tumor that will proceed aggressively, relapse, metastasize and lead to fatal consequences, from a tumor, after removal of which recovery will come.

To determine the prognosis, it is extremely important to classify the tumor according to the degree of differentiation. Differentiation reflects the degree to which malignant mastocytoma cells differ from normal, benign mast cells. The degree of differentiation, as a rule, correlates with the behavior of the tumor, the possibility of its recurrence, the rate of growth and metastasis, and, consequently, the survival of the sick animal.

Table 1

Classification of mastocytes in dogs according to the degree of differentiation

Stage	degree of cell differentiation	cytological signs	probability of recurrence, %
stage I	highly differentiated	layers and homogeneous (same size and morphology), mononuclear cells with stereotypical granulation	25
stage II	moderately differentiated	cell layers are heterogeneous, there are single cells with altered morphology	44
stage III	poorly differentiated	almost all cells of different morphology, many multinucleated, unequal, malformed cells, mitoses	76

However, the classification of a tumor only according to the degree of differentiation does not always give an accurate prognosis, so the clinical classification of the tumor, based on the standard criteria proposed by WHO, is also very important.

SLIDE 9. Clinical classification of mast cellomas in dogs according to WHO criteria

table 2

Stage	Clinical features of the tumor	Probability of recurrence, %
stage I	Solitary tumor without regional lymph node involvement	25
stage II	Solitary tumor with involvement of a regional lymph node	44-100
stage III	Multiple tumors with or without involvement of regional lymph nodes	76-100
Stage IV	Any tumor with distant metastases	100

It is easy to see that from a clinical point of view, it is more difficult to use such a classification, it turns out that from the second stage it is already necessary to apply the most stringent measures, including chemotherapy.

In addition, the position of the mastocytoma on the body of the animal also affects the prognosis. Mastocytomas involving the lips, head, groin, and distal extremities have a poorer prognosis than tumors affecting various parts of the neck and trunk, as well as proximal extremities.

Fast-growing tumors that double in size in a week tend to be more difficult to treat than those that double in size in a year. Naturally, the pathologist will be able to determine the degree of differentiation of tumor cells only after a biopsy and cytological examination. Fine needle biopsy and examination of tumor cells is a must in the investigation of any skin tumor in dogs.

The size of the tumor also matters, the larger the tumor, the more difficult it is to remove it, the longer it exists, the higher the likelihood of metastasis.
And finally, the consistency, the presence of inflammation and adhesions with surrounding tissues, is an important point for the prognosis. If the tumor is well demarcated from the surrounding tissues, sometimes even hanging from the body, and is classified as stage 1 in both classifications, even with a huge size, the animal has a good prognosis for a complete cure.

The possibility of complete removal of the tumor greatly affects the prognosis, therefore, the proximity of the tumor to the nerve trunks and vascular bundles, vital organs, and in areas that are anatomically inconvenient for removal worsens the prognosis. Dogs with stage I or II mastocytomas have a good prognosis, provided they can be completely removed. There is evidence that up to 23% of stage I or II mast cells recur. Any mastocytoma found in the gastrointestinal tract, on the paws, or on the muzzle has a very cautious prognosis. Recent studies have found that tumors in the groin do not have a poor prognosis, which refutes earlier studies.

MASTOCYTE TREATMENT

Treatment of mastocytes in Russia is based on surgical treatment and chemotherapy according to indications, only rare clinics use radiation therapy. Recommendations for chemotherapy are based on the classification of the tumor according to the degree of differentiation and clinical data. Surgery is contraindicated in multiple mastocytomas and poorly differentiated mastocytomas, at least without the support of chemotherapy.

If a poorly differentiated mastocytoma is detected, the veterinarian will most likely prescribe X-ray diagnostics or ultrasound of the internal organs to exclude metastases, as well as biochemical and morphological blood tests to exclude severe anemia and basal cell leukemia, before surgical treatment. Bone marrow biopsy has been abandoned to date, as the data from this study are not very informative.

SLIDE 10. Histological examination

With solitary mastocytomas, surgical excision of the tumor with a wide capture of healthy tissue is always recommended in order to radically excise the tumor. By radical removal of the tumor is meant the removal of at least 3 cm of healthy tissue adjacent to the tumor.

After removal of the tumor, a piece of tissue 0.5 * 1 cm is cut from the edge of the removed tumor from 3-5 sides (depending on the size of the removed tumor), they are placed in 10% formalin, and sent to the pathologist for examination. Histological examination will determine whether the tumor cells remained in the border tissue or not. If the result of the histological examination is negative, then they speak of "clean edges". If the pathologist suspects the presence of mastocytoma cells in the remaining tissues of the site after surgery, we refer to this as "dirty margins".

Early aggressive surgical policy gives the best results in well-differentiated and moderately differentiated mastocytomas. In the presence of "clean edges" after surgery, as a halt, no chemotherapy is required.

Poorly differentiated mastocytomas, multiple tumors, recurrent tumors, or tumors with dirty margins (those that, for anatomical reasons, could not be subjected to more aggressive surgical therapy) often require follow-up or "additional" therapy.

Chemotherapy refers to the administration of certain cytotoxic drugs to delay/prevent tumor growth and spread. Chemotherapy is used after surgery and as monotherapy if surgery is contraindicated (old animal, presence of metastases, late treatment).

SLIDE 11. Typical mast cell treatment options in dogs

A typical chemotherapy regimen will start with prednisolone, and if no positive results are obtained within two weeks, the CVP protocol will be started: cyclophosphamide, vinblastine, and prednisolone. Tagamet will generally be used to minimize stomach irritation from prednisone, as well as counteract the histamines released by existing mast cells.

Table 3

Typical treatment options for different stages of mast celloma

Stage	Processing options
"clean edges"	surgical removal of the tumor no further treatment required
"dirty edges"	surgical removal of the tumor wider surgical removal of tissue with repeated histological examination of the wound edges
"clean edges"	surgical removal of the tumor prednisone for at least 6 months
"dirty edges"	surgical removal of the tumor wider surgical removal of tissue with repeated histological examination of the edges of the wound; prednisolone for at least 6 months

Prednisolone is the most commonly used drug for mast cell therapy. This medication is well tolerated by dogs and is usually given for up to six months. If new tumors do not appear during this time, your doctor may stop the drug completely.

Side effects of prednisone include weight gain, increased appetite and thirst, skin infections, and shortness of breath. Sometimes, there are gastrointestinal disorders, stomach ulcers and pancreatitis. In this case, additional drugs are used to reduce side effects.

SLIDE 12. Therapeutic protocol for inoperable mast cells

Protocol CPV for treatment of mast cells in dogs . It is used for the treatment of multiple tumors, before surgery for large tumors in anatomical areas inconvenient to remove for those tumors that cannot be removed.

Combination chemotherapy can be effective in controlling tumor growth and spread throughout the body over many weeks, months, and even years. A complete cure in this case is not possible, but some dogs tolerate therapy very well and can live up to 2 years or more, while sometimes reaching the age of biological aging.
The 6-month protocol of such therapy includes three drugs (table 4).

Table 4

Therapeutic protocol for inoperable mast cells (CPV protocol)

A drug	Dose	Multiplicity of introduction
prednisolone	individual	daily intake in the form of tablets, administration by the owners is possible, for 6 months.
vinblastine	individual	drip, every 21 days
cyclophosphamide	individual	Orally given by owners on days 8, 9, 10, 11 of a 21 day cycle

Side effects. The side effects of prednisone are discussed above. Vinblastine and cyclophosphamide cause nausea and vomiting. The most severe side effects are associated with the occurrence of systemic infections due to a decrease in the immune status. In addition, massive degranulation of mast cells is possible, which can lead to shock, but these side effects are rare and can be controlled by doctors.

Forecast. Factors that influence the prognosis are the grade of tumor differentiation (better prognosis for well-differentiated tumors and worse for poorly differentiated tumors), adequate surgical resection (clear margins), and location of the tumor. In dogs with low-grade, multiple, or recurrent tumors, or if the tumor has invaded the bloodstream or vital organs, the prognosis is always very poor.

To date, new drugs for the treatment of mast cells have emerged, as Toceranib, a tyrosine kinase inhibitor, was recently approved by the US Food and Drug Administration for the treatment of mast cells in dogs. But unfortunately this drug is not yet available in Russia.

Monitoring after therapy. All dogs that have had their mastocytomas removed should be under constant supervision by veterinary oncologists. Since early detection and subsequent treatment of tumor recurrence increases the likelihood of successful therapy. You will likely be asked to bring your dog in for checkups every 6-8 weeks after surgery, or every 21 days for chemotherapy. Blood tests and tissue aspiration biopsy in the operative area are a necessary condition for full patient monitoring.

SLIDE 13. Mast cell tumor with a good prognosis

Slide 13 shows a tumor in a young boxer female. As you can see, this is a single tumor that does not tend to spread to regional lymph nodes. Cytological examination revealed layers of identical polygonal cells with a large nucleus. The cells have well-defined nuclei, which have a central location. In the cytoplasm, basophilic dust-like granularity is noted. It is clearly seen that this granularity is the same in all the cells presented, more dense along the periphery of mast cells.

According to the degree of differentiation, the tumor is classified as a highly differentiated mastocytoma, according to WHO, a tumor of the 1st stage. With a wide excision of the tumor, the prognosis for this animal is favorable. The dog breed also speaks in favor of a favorable prognosis, as a rule, in boxers the disease proceeds more benignly than in other breeds of dogs.
However, long-term monitoring by veterinary oncologists is necessary.

SLIDE 13. Mast cell tumor with a good prognosis

Slide 14 shows a mastocytoma in a 4 year old female bull terrier. A fairly large tumor on the back of the thigh, regional lymph nodes are not enlarged and painless, their cytopuncture gave a negative result for the presence of mastocytoma cells. The tumor is mobile, not soldered to the tissues.

Cytological examination reveals layers and islets of polygonal cells with pronounced polymorphism (cell sizes and shapes are different). The location of the nuclei in the cells is not the same, in some mast cells the nucleus is located centrally, in others it is eccentric or on the periphery of the cell. The granularity in the cells is homogeneous in morphological characteristics, but its "density" is different, in some mast cells it completely fills the entire cell.

On the basis of clinical data, we classified it as a mastocytoma of the 1st stage, according to cytology as a moderately differentiated mastocytoma, that is, the 2nd stage.
After surgical removal, the edges of the surgical wound were sent for histological examination, and a conclusion was obtained - “clean edges”.
In our opinion, such a tumor does not require additional therapy.

SLIDE 15. Mast cell tumor in a dog (Asian, 8 years old)

Large mastocytoma on the ventral surface of the abdominal wall in an 8-year-old female Asian Shepherd.
The tumor is partially soldered to the surrounding tissues, there is a thickening of the skin over the tumor and around the tumor, the regional lymph node is enlarged, painless, a negative result was obtained during cytological examination of the aspirate from l / y, stage 2 of the tumor according to the clinical classification.

Cytological examination of the tumor revealed the correct layers of monomorphic cells with stereotypical basophilic granularity, which characterizes a highly differentiated mastocytoma, stage 1. Morphological and biochemical blood tests were carried out, they did not reveal any abnormalities, and an operation was prescribed. After surgical removal with a wide excision of the tumor and regional lymph node, chemotherapy was recommended according to the CPV protocol.

The location of the tumor made it possible to carry out excision along healthy tissues, departing from the tumor by almost 10 cm. The owners of the animal refused histological examination of the edges of the surgical wound and chemotherapy, but after 8 months. we observed the dog in our clinic, she was absolutely healthy.

SLIDE 16. Mast cell tumor in a dog (Great Dane, 7 years old)

A small mastocytoma between the fingers of the right limb in a 7-year-old male Great Dane.
The tumor is tightly soldered to the surrounding tissues, has an uneven surface, and areas of inflammation are clearly visible along the periphery of the tumor. Regional lymph nodes are quiet. According to the clinical classification, the tumor is stage 1.

Cytological examination revealed regular layers of monomorphic cells with stereotypical basophilic granularity, which characterizes highly differentiated mastocytoma, stage 1.

Given the proximity of the mastocytoma to the vessels, the impossibility of a wide resection of the tumor without damaging the fingers, a high amputation of both fingers with resection of the tumor was recommended. However, the owners refused to amputate the fingers, after preliminary chemotherapy, the tumor was resected. The study of the edges of the wound was not carried out, at the request of the owners.

After 10 days, when the sutures were removed from the inflamed tissues surrounding the suture, cells were aspirated, and polymorphic cells of a moderately differentiated mastocytoma were found on cytology. The owners of the animal refused further chemotherapy. After 4 months the dog was admitted to the clinic in a serious condition, there was adynamia, anemia, refusal to feed. The dog could not get up. Infusion therapy did not lead to an improvement in the condition of the animal and it died within 3 days from the start of infusion therapy and treatment with histamine blockers. Of course, in this case, it is necessary to take into account the age of the animal

SLIDE 17, 1 8 . mast cell tumor

On these slides there are photographs of 2 mongrel dogs over the age of 10 years. One was diagnosed with a large mastocytoma in the region of the lower third of the chest, in the second upper third of the thigh.

An increase in regional lymph nodes was found. The tumors are ulcerated, soldered to the underlying tissues, according to the clinical classification, both tumors are of the 2nd stage.
Cytological examination revealed stratification of polymorphic cells, a cytological diagnosis of moderately differentiated mastocytoma, stage 2.

After removal of the tumor, both dogs were prescribed a course of prednisolone, and the owners of the animals refused complex chemotherapy. Communication with the owners of one animal was lost, in a 10-year-old male 8 months after surgery and 2 months after the end of prednisolone therapy, the condition is satisfactory, tumor recurrence is not observed.

SLIDE 19. Multiple mastocytoma dogs

In a female boxer at the age of 11 years, multiple tumors were revealed in the form of red nodules from 0.3 to 2 cm, rising above the skin. The nodules are sharply defined, without hair, some nodules are covered with crusts, itching, the dog scratches them. Enlarged pharyngeal and submandibular lymph nodes. Clinical stage of mastocytoma 3rd.

SLIDE 20. Poorly differentiated mastocytoma

Cytological examination of the tumor in this dog revealed irregular layers of polygonal, rounded and irregularly shaped cells. Severe atypia, there are cells with almost no granularity, more like fibrobalsts.

In some cells, the granularity is more pronounced than in others, the size of the granularity is sharply polymorphic, in some cells it is small, and in others it is dusty in the form of large grains and it fills almost the entire cell. With such a cytological picture, we diagnosed a mastocytoma from moderately differentiated to poorly differentiated, stage 3.

At the same time, the general condition of the animal is satisfactory, it is not exhausted, the dog willingly accepts food, sometimes it vomits on an empty stomach. A general blood test revealed slight anemia.
Surgery for such a course of mastocytoma is contraindicated, and the animal was prescribed a course of chemotherapy according to the CPV protocol. To date, 9 months have passed since the diagnosis. the dog is receiving the second course of chemotherapy, the general condition is satisfactory, given the age of the animal, we believe that we have achieved good results.

SLIDE 21-26
(text description)

A series of slides shows animals with the same clinical picture of the corresponding stage 2 mastocytoma, with involvement of regional lymph nodes. It is necessary to note the very difficult location of mastocytes on the front of the head, which sharply worsens the possibility of total excision of the tumor.

In our case, cytological examination revealed sharply polymorphic cells, some of them were multinucleated, the size of granularity in individual cells differed sharply in morphology and size (slide 26, 27, 28). With such a cytological picture, we diagnosed a poorly differentiated mastocytoma, stage 3.

In our opinion, the decision on surgical intervention should be made by a veterinarian in each specific case, taking into account the general condition of the animal, its age and cytological diagnosis. After one course of chemotherapy, we operated on all the animals and in all cases the tumor recurred. All animals were repeated courses of chemotherapy. Both Shar-Pei and the "Asian" tolerated repeated courses of chemotherapy well, the growth of the tumor is restrained, but there is no complete recovery. But the owners of the animals are optimistic and ready for further therapy. During the second course of chemotherapy, the boxer developed signs of heart failure, the owners refused to continue treatment, and we do not know the fate of this animal.

SLIDE 27.

Large mastocytoma in a 5-year-old male. A large ulcerated tumor with an unpleasant odor was found in the area of ​​the right cheek of the animal. Regional lymph nodes are enlarged, chest x-ray shows multiple opacities in the lungs.

The clinical condition of the animal is poor, marked asthenia, adynamia, the dog does not get up. Three days before the dog was admitted to the clinic, she had vomiting blood streaked with dark stools. On the day of admission, the animal refuses to eat, but greedily drinks water, after which it vomits. Complete blood count showed anemia, leukocytosis, thrombocytopenia, biochemical examination revealed hyperazotemia.
The diagnosis of mastocytoma with distant metastases, stage 4 according to the clinical classification.

SLIDE 28. Poorly differentiated mastocytoma

The slide shows a typical picture of a poorly differentiated mastocytoma. All cells are of different sizes, some cells have several nuclei from 2 to 10, the nuclei in the cells are not of the same size and shape. In multinucleated cells, both large and small nuclei can be found. There is a sharp shift in the nuclear-cytoplasmic ratio in favor of the nucleus; in some cells, the nucleus occupies almost the entire cell. The nucleoli in the cells are weakly expressed.

Granularity in cells is polymorphic, both in terms of tinctorial properties and in shape and size; in some cells it is dust-like, while in others it is in the form of large grains of irregular shape. There are always few mitoses in mastocytomas. This picture represents a poorly differentiated mastocytoma, stage 3.

Thus, this animal has an advanced end-stage malignant mastocytoma with clinical signs of systemic mastocytosis and a poor immediate prognosis. After clarifying the situation, the owners decided to euthanize the animal.

SLIDE 29,30, 31. Differential diagnosis of mastocytoma

In our opinion, sometimes there may be problems in differentiating melanoma from mastocytoma. This differentiation is important because chemotherapy and prognosis are different for these tumors. In our practice, we have encountered a case when a melanoma was diagnosed with a mastocytoma with a good clinical prognosis in a medical laboratory. On the basis of an incorrect diagnosis, an incorrect prognosis was made and, accordingly, therapy. The dog was not operated on for a long time and eventually developed a stage 2 mastocytoma.

Why did the doctors make the wrong diagnosis? We have already said that human mastocytoma is a very rare tumor, so rare that some cytologists and histologists, having worked for 20 years or more in the laboratory, have never encountered this problem. Naturally, such specialists lack vigilance and special knowledge in the diagnosis of tumors in dogs and other animals. And when such a possibly and very good specialist gets a canine mastocytoma, he can also make an incorrect diagnosis.

Therefore, when sending material for research to a medical laboratory, a veterinarian must be sure that the specialists of this laboratory are familiar with the problem of diagnosing animal tumors.

Given this problem, we decided to give a few features that distinguish melanomas from mast cells.

1. Melanoma granulation is typically black on a Romanowsky-Giemsa stain, while melanoma granulation is basophilic and dark purple to red in color.
2. The granularity in melanomas is more uniform in the form of coarse dust, and rarely varies in individual cells.
3. Granularity in melanoma cells often lies centrally, and enlightenment is noted along the periphery of the cell, while in mast cells, on the contrary, granularity tends to the edge of the cell.
4. In melanomas, mitoses are very common, while not every mastocytoma has mitoses.
5. In the cytoplasm of melanoma, vacuoles are often found, while in the cytoplasm of mast cells there are no vacuoles.
6. Melanoma is a very delicate tumor and therefore, during the formation of a smear, cells often lose their cytoplasm, bare nuclei remain against the background of black granularity, and mastocytoma cells are almost always intact.
7. Melanomas often form binuclear cells in the form of "fried eggs", while mastocytoma does not form such cells.
8. In 10-15 cases, melanomas may be pigmentless, in which case differential diagnosis is not a problem.
9. In difficult cases, it is always possible to carry out special staining methods that are used in the diagnosis of non-pigmented melanomas.

From the presented material it is clearly seen that mastocytoma is a complex clinical problem that requires a serious assessment, both by clinical veterinarians and pathologists. Diagnosis, prognosis, adequate therapy is based on laboratory tests. To date, all the presented studies can be carried out at the Center for Diagnostics of Animal Diseases of the Rostov Regional Veterinary Laboratory.

In our opinion, the diagnosis of mastocytes is not difficult, but in some cases it may be difficult to assess the stage of tumor differentiation, in which case the complexity of the situation is assessed by the clinician and decides whether or not to perform surgery, and if so, to what extent. But after the removal of all tumors, especially with a good prognosis of the 1st and 2nd stages, in our opinion, it is important to conduct a histological control of tumor removal. Finding out "clean" or "dirty" edges remained after removal of the tumor, this is very important for making a decision on further therapy.

Neoplasms are uncontrolled growths of modified tissues that are unregulated by the body. Tumors in dogs can be localized anywhere in the body. The risk of development increases in animals older than 7 years. Characteristic features of tumors are endless reproduction, qualitative changes in cells, damage to neighboring cells.

Causes and types of tumors in dogs

According to a number of characteristics, neoplasms are divided into malignant and benign.

Benign tumors are characterized by slow growth, the presence of a capsule. Able to reach large sizes. They do not metastasize and rarely recur. However, due to the compression of organs and vessels, severe violations of their function can develop.

Malignant tumors are characterized by constant and uncontrolled cell division, rapid growth. They are not surrounded by a capsule, therefore they are able to grow into the surrounding tissues, leading to their necrosis. They do not always reach large sizes, since irreversible changes from intoxication (up to death) develop quite quickly. Malignant neoplasms metastasize, and if at least a few pathological cells remain among healthy cells after surgical removal, they recur, forming a new tumor.

A single cause of development has not been identified, but the influence of several factors is noted:

• Breed, hereditary predisposition.
• Exposure to carcinogens.
• Irrational nutrition.
• Bad living conditions.

Tumor dog symptoms

Signs differ depending on the location. Superficial neoplasms (skin, mammary glands, and so on) appear in the form of uncharacteristic seals and local visible changes. In the early stages, it is difficult to diagnose, since small nodules are difficult to palpate.

Lesions of internal organs cause changes not only in the function of the affected structures, but also worsen the general condition of the animal. Over time, metabolic disorders, qualitative changes in peripheral blood, and neurological symptoms become noticeable. They can often be suspected by external manifestations.

Breast tumors in dogs

Occupy the third place in frequency among all cases of neoplasms. The highest risk of development is in unsterilized females. Externally, the tumor of the glands of dogs manifests itself as one or more seals, which are most often located close to each other in the area of ​​​​milk packs. They are easily determined by palpation, but accurate confirmation of the diagnosis is possible only after taking a biopsy.

Tumor on dog's stomach

The appearance of a seal on the abdomen may indicate the development of several types of tumors:

• Cancer of the skin or subcutaneous tissue. In the early stages, it manifests itself in the form of small nodules, which merge into a conglomerate in a short time and reach large sizes.
• Peritoneal cancer. The focus is located inside the abdominal cavity on the sheets of the peritoneum, but over time it grows on the anterior abdominal wall and it becomes possible to directly palpate the tumor.
• A tumor in a dog on the abdomen can be a manifestation of damage to the digestive tract. As in the case of the peritoneum, the primary focus is in the cavity. The affected organ (stomach, intestines, liver, spleen) increases over time, which leads to its protrusion and the possibility of direct palpation.

Other localizations

Common localizations of neoplasms:

• Tumor on the paw of a dog. Swelling of a soft consistency may indicate the development of skin or subcutaneous fat cancer. The danger in this case lies in distant metastases, which are carried with the bloodstream to all parts of the body. A solid neoplasm suggests osteosarcoma, a severe bone lesion that eventually involves the entire limb and bones of other parts of the body.
• Ear tumor in a dog. Most often, the appearance of swelling indicates an otohematoma - a rupture of the vessel inside the tissues, not associated with the tumor process. But in some cases, cartilage tissue cancer is detected, which over time can grow deep into the cranium.
• Tumor on the neck of a dog. A neoplasm in the neck may be a sign of the development of a mastocytoma. This is a tumor consisting of transformed mast cells (immunoactive elements, tissue macrophages). Its danger lies in the rapid growth and negative impact on the immune system. Also, over time, compression of the esophagus, upper respiratory tract and main blood vessels is possible, which leads to death.

Diagnostics

Diagnostic measures are aimed at identifying the primary focus of the tumor, its size and the presence of metastases (local or distant). To this end, the following are carried out:

• Clinical, biochemical blood tests.
• Ultrasound of the affected area (if possible).
• Detection of tumor markers in the blood.
• X-ray diagnostics (if necessary - using contrast agents).

After carrying out all the procedures, it is necessary to perform the "gold standard" of oncological diagnostics - taking a piece of pathological tissue (biopsy) with subsequent cytological analysis. After that, the type of tumor will become known, from which cells it has grown, is it benign or malignant.

Treatment of tumors in dogs

Oncoveterinary medicine is a rapidly developing industry in which new methods of therapy are constantly emerging. But surgical removal remains the leading one, taking into account the principles of ablastic and antiblastic. After the intervention, a histological analysis is performed, on the basis of which the question of further chemotherapy or radiotherapy is raised.

A number of neoplasms are treated with chemotherapy (late stages of breast cancer, skin cancer). Such treatment is usually palliative and aims to reduce discomfort to improve quality of life.

Radiation therapy has become less widespread in veterinary medicine. Surgical removal of the tumor in the dog remains the leading method, and radiation exposure is prescribed in the postoperative period to reduce the likelihood of recurrence.

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