Mixed neuroendocrine-non-neuroendocrine carcinoma (MiNEN) in gallbladder with liver metastasis of neuroendocrine carcinoma component: a case report.

Mixed neuroendocrine-non-neuroendocrine neoplasms of the gallbladder are rare with a lack of established standardized therapeutic strategies. We report a case of gallbladder mixed neuroendocrine-non-neuroendocrine neoplasm with liver metastasis of neuroendocrine carcinoma. A patient who underwent radical cholecystectomy for gallbladder adenocarcinoma was detected with increasing liver mass, and hepatectomy was performed. Pathological report revealed neuroendocrine carcinoma. To find primary origin, pathological review of the old specimen from previous cholecystectomy with a slightly different perspective was conducted, where the neuroendocrine component was positively dyed. In conclusion, though it might be impossible to review every pathological result in cases with ambiguous findings, reviewing the previous specimen can be a useful option in diagnosis.