Chronic renal disease in a captive two-toed sloth (choloepus didactylus) with concurrent hepatocellular carcinoma

A 13-yr-old female two-toed sloth (Choloepus didactylus) with a prolonged history of worsening azotemia was necropsied shortly after euthanasia. On necropsy, the sloth had poor body condition, bilaterally shrunken kidneys, and a large neoplastic mass replacing the right liver lobe. Histologic examination demonstrated chronic renal disease with metastatic mineralization as the cause of morbidity. The liver mass was not associated with any known clinical signs and was diagnosed as a solitary and well-differentiated hepatocellular carcinoma. To the authors' knowledge, this is the first report of hepatocellular carcinoma diagnosed in a sloth and the first detailed description of chronic renal disease in this species.