A case of malignant melanoma in a sheep's brain is described for the first time. In a 7-month-old sheep that had been euthanized due to ataxia, post-mortem and histopathologic examinations were performed. Both the brain and the calvarium were heavily infiltrated with neoplastic tissue. Metastases were found in the liver and kidneys. Histomorphology confirmed the gross pathologic impression of malignancy. Congenital melanosis, which is regularly present in the meninx of sheep, could have been the origin of the malignant melanoma in the present case. The young age of the animal appears to favour this supposition. This case demonstrates that even in farm animals - including sheep - a neoplasm should be considered as a differential diagnosis in diagnostically doubtful cases.
Keywords: CNS; Melanocyte; bone; kidney; liver; meninx; metastasis; neoplasm.