Mammary gland adenocarcinoma in a mandrill (Mandrillus sphinix)

A 22-year-old female mandrill (Mandrillus sphinix) with continuously growing mass at the right mammary gland area was found dead, and a postmortem examination was performed. At necropsy, an elevated firm subcutaneous mass about 5 cm in diameter was present at the right mammary gland area. Axillary, mediastinal, and tracheobronchial lymph nodes were enlarged 2 to 4 times their normal sizes. Numerous metastatic foci 2 to 5 mm in diameter were scattered in the lung. Histologically, the tumor was diagnosed as mammary gland adenocarcinoma. Metastasis to the regional lymph nodes and lung was also confirmed. This is the first reported case of a mammary gland tumor in mandrill in Asia.