[A case of osteosarcoma in a white polar bear]

A male polar bear was caught at the Franz Josef Land at the age of 1 year and then lived in Moscow ZOO for 6 years. Thickening of the distal part of the right hind limb was noted in 1993. Destructive changes in the region of epymetaphysis were observed roentgenologically suggesting osteolytic osteosarcoma. The bear was euthanized and, at autopsy, the tumor had 15 cm in diameter and the distal parts of fibula and tibia were completely destroyed. Numerous cavities containing blood and necrotic areas were observed in the central parts of the tumor. The tumor was firm with hemorrhages in the peripheral parts. Multiple confluent metastases were found in all lobes of both lungs with no metastases in other organs. No radioactivity was found in the tumor tissue and bone at radiochemical analysis.