Hepatoid microcarcinoma of the pancreas: a case report and review of the literature.

Hepatoid differentiation in pancreatic carcinoma is a rare phenomenon. It occurs either as a pure form or as a component with other subtypes. Herein, we report a 52-year-old man with an ampullary large cell neuroendocrine carcinoma presenting with obstructive jaundice for 2 months. A 0.5-cm nodule was found in the pancreatic head. Morphologically, the nodule was composed of exclusively hepatocytic tumor cells and sinusoids with dysplastic cytology and capsular invasion. The patient did not have a hepatic mass or ectopic normal liver tissue. This is the first reported case of ampullary large cell neuroendocrine carcinoma coinciding with a pancreatic hepatoid microcarcinoma. The clinicopathological features of pancreatic hepatoid carcinomas and their histogenesis are discussed.