Melanoma metastático em caprino / Metastatic melanoma in a goat

ABSTRACT

Background: Melanoma is one of the 5 neoplasia types of that most frequently affect skin and subcutaneous tissue, especially in Northeastern Brazil, where there is a high incidence of solar rays. It is a tumor that affects melanocytes and ischaracterized by diverse morphologies ranging from round to polygonal cells, including epithelioid cells, spindle cells,star-shaped or with a mesenchymal appearance, and presenting large amounts of melanin in the cytoplasm. The pigmentcan be found in the cytoplasm of macrophages, indicating the phagocytic activity at the site. The nucleus is basophilic,and mitotic figures are not numerous.Case A 12-year-old female goat with a history of nodular lesion in the nasal region with progressive increase and recurrence was submitted to clinical evaluation. The tumor presented suggestive characteristics of melanoma, such as elevatedirregular and surface with a central region of black colored skin. After surgical removal of the nodule, recurrence wasobserved in infra-orbital and parotid regions with infiltration of the mandible. Hence, the malignant behaviour of thetumor indicated euthanasia of the animal. The owner authorized the procedure and the individual was then submitted tonecropsy at the Animal Pathology Sector of the Federal Rural University of Pernambuco, Academic Unit of Garanhuns(UAG/UFRPE). At necropsy, findings included a tumor in the parotid region with infiltration to the mandible, multipletumors of black or grayish-white color in liver, multifocal nodules of grayish color in the right kidney and left kidney alsohad tumors of the same colorations, in the thoracic cavity, blackened spots were...(AU)