Papillary cystadenocarcinoma of the mammary gland with metastases to the gastrointestinal tract in a Himalayan brown bear (Ursus arctos).

A 17-yr-old, multiparous female brown bear (Ursus arctos) bred in captivity at the Himalayan Nature Park, Kufri, Shimla, Himachal Pradesh, India, died after a short progressive illness of 2 wk duration. Clinically, the bear had dyspnea and was pyretic, inappetent, and lethargic. Within the right pectoral mammary gland was an 11-cm diameter, round, firm, subcutaneous mass. At postmortem examination, the mammary gland revealed a well-differentiated, multinodular infiltrative mass with multiple nonuniform cystic spaces. These cystic spaces were filled with watery, opaque white to yellow contents. Additionally, multifocal, nodular, ovoid intraluminal masses that extended transmurally from the mucosal surface to the serosa were detected in the duodenum and jejunum. Histopathologic examination revealed papillary cystadenocarcinoma of the mammary gland with metastases to the intestine, which has not been documented previously in Himalayan brown bears.