According to foreign researchers, mastocytoma is one of dogs' most common (7–12 %). The study aimed to study the features of clinical manifestations of cutaneous mast cells according to the criteria of clinical TNM classification and pathomorphological (cytological and histological) verification of neoplasia according to the two-stage Kiupel classification. We analyzed 24 cases of cutaneous mastocytoma in dogs. During 2016–2020 underwent an entire course of diagnostic and therapeutic measures in the Department of Surgery and Clinic of Small Pets of Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv. According to the criteria of the international clinical TNM classification at the time of admission to the clinic in 7 (29.2 %) dogs established stage I of the tumor, 10 (41.7 %) – II, 6 (25 %) – III, and 14.1 %) animals – stage IV. Based on cytological evaluation of biopsy material selected from tumors and regional lymph nodes, low-grade mastocyte was found in 17 (70.8 %) animals, and in 7 (29.2 %) cases, neoplasia was characterized as high-grade. Histological examination of excisive material selected during surgery in 16 (66.7 %) dogs verified mastitis of low malignancy and, accordingly, in 8 (33.3 %) animals MCTs of high malignancy. The sensitivity of the pathomorphological study was 87.5 % and the specificity of 95.8 %. It has been proven that cutaneous mastocytoma belongs to neoplasms with specific clinical manifestations. Therefore, targeted biopsy should be performed under ultrasound control, fine-needle biopsy (FNA), and material selection for the cytological examination. A comparative analysis of clinical TNM classification data and the results of two-stage histological classification (Kiupel) showed that the size of the tumor and the degree of its malignancy are interrelated, as there is a trend in which, along with increasing T, the clinical TNM classification of cancer, the number of cases of verification of malignant neoplasms is also growing. It was also found that the malignant course of the disease is characteristic of mast cells localized in dogs in areas of the body freely available for permanent injury (limbs, groin, perineum, neck). The obtained data will supplement the evidence of researchers from other countries on the histological structure of tumors and expand knowledge about the pathogenesis of mastocytoma in dogs.

The article deals with the results of monitoring searches on the spread of cancer in dogs and conducted the analysis of incidence rates of animals depending on breed, gender and age. Research were performed during the 2016-2019 years on 2015 dogs, who came to the educational research clinics of the Department of Surgery and Diseases of Small Animals named after Stepan Gzhytskyj LNUVMB. Cancer patients sick dogs (n = 259) of diff erent breeds and genders, aged from 4 months to 16 years, were the subject of research. It was installed, that in the structure of surgical diseases of dogs the share of neoplasia averages 12.85% (10.2-14.9% by years of observation). Among neoplasms, breast neoplasia (35.1%) and skin tumors (29.8%) were most commonly reported, less frequently - tumor lesions of the organs of the reproductive system (13.9%), neoplasia of the internal organs (10.5%), neoplasms in the head and neck (6.6%). Neoplastic lesions of hematopoietic and lymphoid tissues (2.3%) and tumors of bones and joints (1.9%) were characterized by sporadic cases. In 20% of dogs, there was a simultaneous tumor lesion of diff erent nosological forms; most often there are skin and breast tumors, less often skin and tumors in the head and neck. It was also installed, that among 259 dog cancer patients, 23.2% of the animals were outbred and 76.8% were purebred (with more than 40 breeds); males accounted for 48.2% and females for 51.8%. The highest incidence of neoplasia was found in animals between 7 and 12 years of age; the median incidence was 8.5 years, and fashion (the highest number of diseased animals) was 9.5 years. It is found out that the dynamic growth of oncological diseases during 2016-2019 occurred, for the most part, by increasing the number of animals with skin tumors and, to a lesser extent, internal organs. Skin tumors were characterized by a wide variety of nosological forms and were diagnosed in dogs of all ages, as well as diff erent breeds and genders. According to the results of histological verifi cation, 42 or 54.7% of animals had benign tumors of the skin and malignancies in 35 or 45.5% of cases. It was also installed, that benign tumors were mostly represented by papilloma (26.0%), less frequently - lipoma (13.0%), dermatofi broma (10.3%), trichoepithelioma (5.2%). Malignancies are distributed as follows: mastocytoma (18.2%), squamous cell carcinoma adenocarcinoma (2.6 %), spindle cell sarcoma (2.6%) fi brosarcoma (1.3%). Therefore, the reported prevalence of spontaneous neoplasia in dogs in our region certify that skin tumors are currently the most important and promising area for further research. Key words: dogs, neoplasms, spread, clinical classifi cation of tumors, skin neoplasia, histological type of tumors.

According to foreign researchers, mastocytoma is one of the most common (7-12 %) skin tumors in dogs. This neoplasia is caused by excessive proliferation of mast cells and characterized by a specific clinical course, unpredictable biological behavior and prognosis. Researches of clinical and morphological features of mastocytoma in geographical populations of Ukraine has not only scientific and general biological interest, but also important practical significance. The purpose of the research was to establish the frequency of spreading, the features of the clinical ostent and pathogenesis of cutaneous mastocytoma in dogs in conditions in Lviv and in the suburban zone of the regional center. The research was performed on dogs with skin tumors (n = 128), including 24 of them with mastocytoma, who came to the Department of Surgery and Clinic of Small Pets of Stepan Gzhytskyj LNUVMB during 2016–2020. The diagnosis on mastocytoma was verified by the results of physical examination and cytological examination of biopsy material of neoplasms. It was found that in the structure of oncological diseases of dogs the share of skin neoplasms was 32.16 %. Among animals with skin neoplasms, mastocytoma was diagnosed in 18.75 % of dogs aged 4 to 16 years. The highest incidence rates were found among animals aged 8 to 11 years; the median incidence was 9.5 years and fashion – 9 years. In terms of breeds, cutaneous mastocytoma was found in dogs of the breed: Rottweiler – 16.7 %, Sharpei – 12.5 %, Staffordshire Terrier – 12.5 %, Labrador – 8.3 %, Boxer – 8.3 %, Doberman – 8.3 %, chow-chow – 8.3 %. At the same time, the German Shepherd, Alabai, Spaniel, French Bulldog and Pug cases of the disease were isolated (4.2 %). Among sick animals, dogs accounted for 54.2 % and females for 45.8 %. It was found that in 41.7 % of the studied animals the rate of neoplasia was extremely rapid, because in 56.5 ± 1.91 days the tumors were doubled in size, which is evidence of significant aggressiveness of tumor growth. In 29.2 % of dogs the time of doubling the size of the primary tumor reached 122.1 ± 10.6 days, in 20.8 % of dogs the period of tumor development lasted for two years. In 8.3 % of dogs, the dynamics of neoplasia development is not clear. Sonography has shown that skin mastocytomas are usually visualized as heterogeneous, with uneven edges and fuzzy contours hypoechoic structures. Visualization of solid hypervascular foci with central type of vascularization, on the background of diffuse infiltration of neoplasia in the deeper layers of the skin and subcutaneous tissue, with a pronounced perinodular inflammatory reaction of the surrounding tissues is a sign of malignancy of the mastocytoma. The generalization of the neoplastic process in the internal organs was found, in particular the spleen, may indicate a predominance of the hematogenous route of metastasis of the mastocytoma. The obtained data complement and expand knowledge about the pathogenesis of mastocytoma in dogs, and also highlight the frequency of spreading and course features of this oncological pathology in a separate geographical population of Ukraine.

According to foreign researchers, mastocytoma is one of the most common (7–12 %) skin tumors in dogs. The study aimed to study the features of the clinical manifestation of cutaneous mast cells according to the criteria of the clinical TNM classification. We analyzed 24 cases of cutaneous mastocytoma in dogs during 2016–2020, of diagnostic and therapeutic measures in the Department of Surgery and Clinic of the Small Pets Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv. According to the criteria of the international clinical TNM classification at the time of admission to the clinic in 7 (29.2 %) dogs established stage I of the tumor, 10 (41.7 %) – II, 6 (25 %) – III, and 1 4.1 %) animals – stage IV. Based on cytological evaluation of biopsy material selected from tumors and regional lymph nodes of low-grade mastocytes, 17 (70.8 %) animals were found, and in 7 (29.2 %) cases, neoplasia was characterized as high-grade.