Clinical, imaging and pathological features of hepatic carcinosarcoma in a sugar glider (Petaurus breviceps)

A 5-year 6-month-old, neutered, male sugar glider (Petaurus breviceps) presented for lethargy. Plasma biochemistry revealed severely elevated alkaline phosphatase and moderate hypercholesterolemia. A heterogenous liver and a right abdominal mass were noted on abdominal ultrasonography. Computed tomography revealed an enlarged liver with ill-defined hypoattenuating regions and a heterogenous mass arising from the caudate lobe. Cytology of the liver was consistent with low-grade mixed lipid and hydropic vacuolar change and mild to moderate mixed to mature lymphocytic infiltrate. Liver biopsies were declined, and the patient was managed with silymarin and prednisolone. Serial bloodwork and abdominal ultrasonography revealed persistently elevated alkaline phosphatase and progressive heterogenous hepatomegaly and hepatic nodules. The sugar glider died over 2 years after original presentation. On postmortem examination, there was a poorly differentiated hepatic neoplasm, with immunohistochemistry most consistent with a carcinosarcoma. In future cases, hepatic biopsies could be considered for sugar gliders presenting with hepatic masses when cytology is unrewarding.