Primary Hepatic Neuroendocrine Carcinoma Coexisting with Hepatocellular Carcinoma in Hepatitis C Liver Cirrhosis: Report of a Case

Primary hepatic neuroendocrine carcinoma is an extremely rare tumor of the liver. We herein describe a case of primary hepatic neuroendocrine carcinoma with lymph node metastases, coexisting with hepatocellular carcinoma, on a background of hepatitis C cirrrhosis, in a 72-year-old man. Abdominal ultrasonography and computed tomography (CT) showed a tumor (3 cm in diameter) in Couinaud's hepatic segment 8 (S8) with regional lymph node metastases. Whole-body CT, magnetic resonance imaging (MRI), and endoscopy did not reveal primary lesions outside the liver. Feridex MRI and [(18)F]fluorodeoxyglucose positron emission tomography were strongly suspicious of malignancy. A limited hepatectomy with regional lymph node dissection was performed. Histopathology, immunohistochemistry, and electron microscopy confirmed a diagnosis of primary neuroendocrine carcinoma on a background of liver cirrhosis. A tumor (1.5 cm in diameter) found in hepatic S5 at operation was also simultaneously resected, and histologically diagnosed to be hepatocellular carcinoma. We also review previous reports of hepatic neuroendocrine carcinoma and discuss hypotheses for the histogenesis of these tumors as well as prognostic implications. Given the background cirrhosis and coexisting hepatocellular carcinoma, we speculate that one of the hepatocellular carcinomas underwent neuroendocrine differentiation.