Tumor of the liver (hepatocellular and high grade neuroendocrine carcinoma): a case report and review of the literature.

We describe a rare hepatic collision tumor composed of a hepatocellular carcinoma and a high-grade neuroendocrine carcinoma. The patient, a 50-year-old man, underwent a partial hepatectomy because of a 5.0-cm mass. The tumor had two distinctive patterns. The majority of the tumor was a high-grade neuroendocrine carcinoma with features of a small cell carcinoma that was positive for chromogranin, synaptophysin, and cytokeratin 19 and negative for hepatocellular antigen and alpha-fetoprotein (AFP). The second component was a moderately differentiated hepatocellular carcinoma that was positive for hepatocellular antigen and AFP and negative for neuroendocrine markers. The two tumors were separated by fibrous bands. In areas where they collided, there was no transition or intermingling of cells between the two components, thus, it is different from the combined type of tumors. After removal of the tumor, the patient had intrahepatic and mesenteric recurrences within a follow-up period of 16 months.