Metastatic cutaneous melanoma in equine: anatomopathological aspects

Cutaneous melanoma is a neoplasm originating from melanocytes. In equines, a variable incidence of 6 to 14% of the total tegumentary neoplasms. The occurrence of metastasis is uncommon. In this sense, the objective was to describe a case of metastatic cutaneous melanoma in the equine species. A 15-year-old mixed-breed mare, died and was sent to perform necroscopic examination. During the processing of samples of various tissues and organs submitted to histopathological analysis. The main macroscopic alterations observed corresponded to proliferations in cutaneous glandular tissue of the udder, mammary lymph nodes, heart, lung, parietal pleura, liver and spleen, with sometimes blackened cutting surface. The morphological pattern, throughout the udder tissue extension, was compatible with melanoma. Histopathological evaluation of the two affected organs revealed a similar microscopic appearance. When associating the anatomopathological findings, a picture of metastatic cutaneous melanoma was defined. Melanoma should be considered as one of the possible diseases that affect the integument wrapping of the udder of mares of advanced age. A thorough evaluation of the animal is useful, since the metastatic potential is a real possibility.