Hepatocellular carcinoma arising from ectopic liver tissue in the pancreas

Liver tissue ectopia is a well-documented phenomenon. Rarely, hepatocellular carcinoma arises from the ectopic liver tissue. In this paper, we report a case of a primary, well-differentiated hepatocellular carcinoma arising from ectopic liver tissue in the pancreas. The patient is a 58-year-old Hispanic man with no history of underlying liver diseases or chronic pancreatic diseases. Patient presented with a several days history of abdominal pain with radiation to his right upper quadrant. Imaging study revealed a 3.7 x 3.3-cm mass in the distal pancreas. No other lesions were identified. Preoperative fine needle aspiration revealed blood and atypical hepatocytes. The patient underwent distal pancreatectomy and splenectomy for suspected neuroendocrine tumor. Gross examination revealed a well-circumscribed 3.3-cm, beige-tan, pseudolobulated tumor with focal areas of hyperpigmentation. A microscopic examination revealed hepatoid cells arranged in a trabecular pattern with focal bile pigment. Immunohistochemistry study showed that the tumor cells were reactive with hepatocyte antigen (Hep par 1), alpha-1 antitrypsin, but negative for synaptophysin and chromogranin. Immunostain for polyclonal carcinoembryonic antigen showed a typical bile canalicular pattern. These results support that this tumor in the pancreas is hepatocellular carcinoma, most likely arising from ectopic liver tissue within the pancreas.