Lymphosarcoma in a Brown Bear (Ursus arctos)

An example of lymphoblastic lymphosarcoma was diagnosed in a 7-year-old male brown bear (Ursus arctos) that died after having a 7-month history of depression, anorexia and watery diarrhea. Grossly the mesenteric lymph nodes were enlarged to approximately 4 to 6 times their normal size and histologically diagnosed as lymphoblastic lymphosarcoma. The small intestinal mucosa was corrugated and had severe mural thickening due to infiltrated neoplastic cells. Hepatic metastasis was also noted. the mother of this bear which died at the age of 20 also had similar gross changes on necropsy, but histological examination was not performed at that time and therefore the exact type of neoplasm remained to be determined. Since the daughter also died of neoplasm, genetic factor could be suspected in this family. This is the first reported case of lymphosarcoma in Ursidae in Korea. As an incidental finding, endogenous lipid pneumonia was noted in the lung.