A case of primary hepatic mixed neuroendocrine-non-neuroendocrine tumor (MiNEN) associated with gallbladder carcinosarcoma.

A woman in her seventies visited our hospital because of abdominal pain. Multiple hepatic tumors were detected and a liver biopsy revealed mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN), which was composed of cholangiocellular carcinoma and neuroendocrine tumor (NET). Diagnostic imaging ruled out primary malignancies other than the liver and identified that the tumor originated from the liver. Because a predominant and aggressive part of the tumor was considered to be cholangiocellular carcinoma, gemcitabine and S-1 were used as first-line treatment. After the treatment, octreotide acetate was administered for the NET component, followed by transcatheter arterial embolization. Subsequently, her gallbladder (GB) rapidly swelled with biliary tract obstruction, and cholecystectomy revealed carcinosarcoma of the GB. She is still undergoing treatment at 44 months after diagnosis. Herein we report this case of primary hepatic MiNEN consisting of cholangiocarcinoma and NET, followed by GB carcinosarcoma. This is the first case illustrating that a multidisciplinary treatment approach for MiNEN accompanied with carcinosarcoma, involving assessment and treatment targeting the most aggressive component, can result in a long survival time.