Resumo

DOMITROVIC, H.A. et al. Tumor ovárico semejante a tumor de células epitelioides perivasculares (PEComa) en boga (Leporinus obtusidens). Rev. vet. [online]. 2015, vol.26, n.1, pp.63-68. ISSN 1669-6840.

Ovarian neoplasia is scarcely mentioned in teleosts, being specimens from ornamental species the most frequently reported. This paper describes for the first time the characteristics of a spontaneous ovarian tumor from an adult specimen of boga (Leporinus obtusidens) obtained from the Paraná River (Argentina). Macroscopically, in the abdominal cavity and in correspondence to the posterior third of ovarian, an irregular firm deformation with encapsulated cystic appearance was observed, presenting adherences between the ovarian membrane and the dorsal peritoneum. Samples of tumor and ovarian tissues were fixed in formalin and embedded in paraffin. Sections of 3 micron thickness were stained with routine, histochemistry and immunohistochemistry techniques. Histopathological observation of tumoral tissue revealed cystic structures and proliferating tumoral tissue. An amorphous material was found inside the cystic structures and was defined by a cellular coating of epithelioid appearance. The proliferating tumoral tissue showed procea pleomorphic aspect, being found areas of myxoid connective tissue with fusiform cells and abundant capillaries, mucoid tissue areas and polygonal cells placed isolated or forming islets near to the capillaries. The polygonal cells showed eosinophilic cytoplasm and large nuclei with loose chromatin and evident nucleoli, being observed some mitotic figures. These cells proliferated to form an epithelioid appearance tissue with intercalated capillaries, taking a spongy aspect on the periphery of some capillaries with a significant reticular fibers density. Also, thin collagen fibers and inflammatory infiltrate in the outermost zone of the tissue was observed. By analogy with the types described in mammals, it can be established that the lesion observed in this fish ovary corresponds to a mesenchymal origin tumor, witha morphology that resembles the perivascular epithelioid tumor (PEComa)

Palavras-chave : fish; Leporinus obtusidens; ovarian neoplasia; PEComa.

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