A 3.0 kg male South American lungfish (Lepidosirea parodoxa) presented with a history of longstanding tan colored Masses protruding bilaterally from the opercular openings. Radiographs and blood samples were analyzed and surgical removal was elected. Using ketamine HC1 at a dose o f 150mg IM (50mg/kg) and 251ng IV (8.3mg/kq) the animal was prepared for surgery. The masses were found to invade into the gill arches bilaterally and a debulking procedure was performed using an electrosurgical technique.

Histopathology yielded a diagnosis of a neoplasm most likely originating from muscle tissue. Fibromas have been previously reported in lungfish however the histologic morphology is more suggestive of a muscle-origin tumor. Discussion will include review of special stains and procedures including immunocytochemistry and electron microscopy which were used to delineate the origin of the tumor.