Combined primary neuroendocrine carcinoma and hepatocellular carcinoma of the liver.

We report a unique case of combined primary neuroendocrine carcinoma (NEC) and hepatocellular carcinoma (HCC) of the liver in a 65-year-old male patient. The patient underwent segmental resection of the liver and regional lymph node dissection for a tumor mass that measured 7.5 cm in diameter in the right lobe, with regional lymphadenopathy. Histologically, the hepatic tumor was composed of predominantly small-cell NEC, but admixed with a small island of moderately differentiated HCC. We speculate that the NEC originated from a poorly differentiated tumor clone of an HCC that underwent neuroendocrine differentiation, and that this tumor was now at the end stage of the transitional period from HCC to NEC, based on the small amount of disappearing HCC. Ki-67 and p53 expression were higher in the NEC than in the HCC, and the lymph nodes showed only metastatic NEC. Therefore, this kind of tumor had a more aggressive clinical course in accordance with being an NEC rather than a conventional HCC. Three months after operation, the patient had multiple recurrent tumor nodules within the liver, spreading the metastasis to the adrenal glands and para-aortic lymph nodes. The patient died 1 year after operation.