Mammary Adenocarcinoma with Widespread Metastasis in a Lion (Panthera Leo)

A 15 year old female African lion (Panthera leo) was necropsied after its sudden death. The necropsy showed a mammary gland lesion measuring 10 cm in diameter and numerous white nodules with variable size in the liver, spleen, uterus, lungs and the heart. The histopathological examination showed that the neoplastic formation in the mammary region was a simple tubular carcinoma with metastases on the other organs. Upon immunohistochemical examination, the neoplastic cells expressed cytokeratins while the stroma of the tumour expressed vimentin. The proliferation index Ki-67 was moderate. Based on the macroscopic, histopathological and immunohistochemical findings, the neoplasia was diagnosed as a simple tubular mammary carcinoma.