Primary hepatic neuroendocrine tumor: A case report and literature review.

Primary hepatic neuroendocrine tumors (PHNETs) are extremely rare and difficult to distinguish from other liver tumors, such as hepatocellular carcinoma (HCC) and cholangiocarcinoma, based on medical imaging findings. A 70-year-old man was referred for evaluation of liver mass incidentally discovered on abdominal computed tomography. The characteristic finding from dynamic liver magnetic resonance imaging led to a diagnosis of HCC. The patient underwent right hepatectomy. Histopathological and immunohistochemical examination revealed grade 2 neuroendocrine tumor. The postoperative 24-h urinary excretion of 5-hydroxy-indolacetic acid was within the normal range. Further imaging investigations were performed. No other lesions were found making probable the diagnosis of PHNET. This case shows that the diagnosis of PHNET is a medical challenge, requiring differentiation of PHNETs other hepatic masses and exclusion of occult primary neuroendocrine tumors. The diagnosis of PHNET can be ascertained after long term follow-up to exclude another primary origin.