Metastatic melanoma in a Saanen goat: clinical, ultrasonographic and anatomopathological aspects - case report

• Published in: Arquivo brasileiro de medicina veterinária e zootecnia 2021-08, Vol.73 (4), p.827-833
• Main Authors: Conceição, A.I., Cajueiro, J.F.P., Mendonça, C.L., Souza, M.I., Afonso, J.A.B., Oliveira, J.B.S., Santos, R.L., Arenales, A.
• Format: Article
• Language: English
• Subjects: dairy goat; diagnostic imaging; metastasis; VETERINARY SCIENCES
• ISSN: 0102-0935; 1678-4162; 1678-4162
• DOI: 10.1590/1678-4162-12336

ABSTRACT This report describes clinical, ultrasonographic and anatomopathological findings in a case of metastatic melanoma in an adult Saanen goat. Clinically, the goat had apathy, an intra-abdominal palpable firm structure, and exophytic keratinized areas on the skin of the udder. Ultrasound revealed non-encapsulated oval structures, with heterogeneous echogenicity and marked central and peripheral vascularization, and hypoechoic hepatic multifocal to coalescent areas. In the udder, there were non-encapsulated oval structures with heterogeneous echogenicity and hyperechoic center surrounded by hypoechogenic tissue. Grossly, there were black multifocal to coalescent areas in the liver, as well as black nodules in mammary and mesenteric lymph nodes, uterus, spleen, and myocardium. Microscopically, multifocal melanocytic neoplastic proliferation was observed in the dermis and junction of the udder epidermis. Most of the neoplastic cells had cytoplasmic granules of melanin. In the liver there were areas of neoplastic tissue compressing the adjacent parenchyma, with central foci of necrosis, mild desmoplasia, and multifocal infiltration of malignant cells into the adjacent tissues. Similar findings were observed in the mammary and mesenteric lymph nodes, uterus, spleen, and myocardium, which characterized metastatic melanoma. Ultrasonography played a key role for establishing the diagnosis of a metastatic melanoma and helped establish a proper clinical management protocol. RESUMO Este relato descreve os achados clínicos, ultrassonográficos e anatomopatológicos em um caso de melanoma metastático em uma cabra Saanen adulta. Clinicamente, a cabra apresentava apatia, estrutura firme palpável intra-abdominal e áreas exofíticas queratinizadas na pele do úbere. A ultrassonografia revelou estruturas ovais não encapsuladas, com ecogenicidade heterogênea e marcada vascularização central e periférica, além de áreas hepáticas multifocais a coalescentes hipoecoicas. No úbere, havia estruturas ovais não encapsuladas, com ecogenicidade heterogênea e centro hiperecogênico circundado por tecido hipoecogênico. Macroscopicamente, havia áreas pretas multifocais a coalescentes no fígado, bem como nódulos pretos nos linfonodos mamários e mesentéricos, no útero, no baço e no miocárdio; microscopicamente, proliferação neoplásica melanocítica multifocal foi observada na derme e na junção da epiderme do úbere. A maioria das células neoplásicas apresentava grânulos citoplasmáticos de m