A massive hepatic tumor demonstrating hepatocellular, cholangiocarcinoma and neuroendocrine lineages: A case report and review of the literature.

INTRODUCTION: Mixed hepatocellular and cholangiocarcinoma tumors (MHCC) are described in the literature, as are the more rare mixed adenoneuroendocrine carcinomas (MANC) of hepatobiliary origin. Only two cases of tumors with characteristics of all three histologies/phenotypes have been previously described in one Chinese study. PRESENTATION OF CASE: Herein we report clinical, microscopic and molecular features of a 25cm mixed hepatic tumor with hepatocellular, cholangiocarcinoma and neuroendocrine differentiation arising in an otherwise healthy 19-year-old North American Caucasian male without any identifiable risk factors. DISCUSSION: The patient underwent multimodality imaging and the tumor was biopsied preoperatively, and it was initially interpreted to be hepatocellular carcinoma fibrolamellar type. A left trisegmentectomy with lymphadenectomy was performed and the tumor was definitively diagnosed based on the surgically resected specimen. Integrated microscopic and molecular features defined the differing biological aggressiveness of growth pattern components. Cases in the literature of MHCC and rare cases of MANC have largely undergone aggressive surgical resection as well, however the majority of studies on mixed hepatic tumors to date reflect Eastern patient cohorts and populations with underlying liver disease, thereby limiting extrapolation on management or outcomes in this case. CONCLUSION: This is one of the only reports of a hepatic tumor arising from hepatocellular carcinoma, cholangiocarcinoma and neuroendocrine lineages. Increased awareness of this tumor type may optimize improve future management.