Incidental Collision Tumor of Hepatocellular Carcinoma and Neuroendocrine Carcinoma.

The composite tumors of the liver are very rare, including the coexistence of HCC (hepatocellular carcinoma) with NEC (neuroendocrine carcinoma). The rare occurrence of these tumors necessitates more reported cases in order to fully understand their clinical characteristics, behaviors and treatments. Herein is described an incidental collision tumor of HCC-NEC, along with a review of the literature focusing on their clinicopathological findings and prognosis. The tumor presented here was found incidentally in the hepatectomy specimen of a 56-year-old man who had undergone liver transplantation for rapidly progressive liver failure because of alcoholic hepatitis and cirrhosis. Imaging and laboratory examinations did not demonstrate tumor-related findings. During macroscopic examination, two sharply defined and distinctive areas (1.7 cm and 0.6 cm dimension respectively) were detected among the cirrhotic nodules. The characteristic histopathological features and immunohistochemical findings allowed a diagnosis of HCC-NEC to be made. There was no evidence of recurrence and metastasis after 10 months following surgery. The present case and review revealed that these tumors are frequently found in older ages and males. Although serum markers are valuable in the discrimination of malignant tumors, their absence cannot completely rule out composite HCC-NEC. Diagnosis requires a comprehensive histopathological evaluation together with immunohistochemistry. The NEC component might influence the treatment strategy and eventually the outcome of the patient. In conclusion, the rare occurrence of HCC-NEC and the lack of diagnostic clinical signs and symptoms do not exclude their consideration in the differential diagnosis of liver tumors, especially in patients with the chronic liver disease.