Clinical characteristics of mastocytoma in dogs
Authors: Ivashkiv B. B. , Mysak A. R. , Pritsak V. V. 
Published: September 2020

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.