Amelanotic melanoma in a crab-eating fox (Cerdocyon thous)

The accelerated and disordered division of cells in the body results in neoplastic processes. Melanoma, a malignant neoplasm, is described in domestic dogs, and it has already been reported in wild carnivores. During a routine examination of an adult crab-eating fox (Cerdocyon thous), approximately 14 years old and kept at the Sorocaba Zoo, presented a mass in the perineal region. A surgical procedure was realized to remove the mass, as it presented ulceration. The patient’s recovery was satisfactory and the animal was medically discharged. Cytological, histological and immunohistochemical tests were performed, and the results indicated amelanotic melanoma. This is the first report of amelanotic melanoma in a crab-eating fox kept under human care.