Spontaneous hepatocellular carcinoma in Saimiri boliviensis.

Hepatocellular carcinomas are rare in nonhuman primates. In this study we found the first naturally occurring hepatocellular carcinoma in a Squirrel Monkey (Saimiri boliviensis) of at least 24 years of age. In the necropsy, the liver was cirrhotic and contained multiple tumorous nodules, which varied in diameter from 3 to 15 mm. The lungs also contained small neoplastic masses. In the histological study, samples of liver, lungs, and other organs were taken and fixed in 10% buffered formalin, embedded in paraffin, cut at 5 microns, and colored with hematoxylin and eosin. The histological study of the liver permitted the detection of multiple masses of neoplastic liver cells in a closely packed trabecular configuration surrounded by a well-developed capillary basement membrane. Cirrhotic changes also were observed in the liver. The histological study of the lung confirmed the metastasis of the hepatocellular carcinoma. Metastasis was not found in other organs.