Komson Wannasai1, Witanee Na Chiang Mai2, Sunhawit Junrungsee3, Sarawut Kongkarnka1, Nirush Lertprasertsuke 1Department of Pathology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 2Department of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 3Department of Surgery, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Received : 15 September 2014 ; Accepted : 25 October 2014
Case presentation: A 68-year-old woman presented with hepatic metastasis. She had been performed cholecystectomy at a provincial hospital for symptomatic gallstones and was diagnosed as poorly differentiated adenocarcinoma of the gallbladder. The follow-up hepatic segmentectomy revealed a malignant small round tumor composed of nests of cells containing small nuclei with fine granular chromatin and inconspicuous nucleoli. The tumor cells were immunoreactive for chromogranin A. Metastatic small cell carcinoma was diagnosed. The gallbladder lesion was reviewed and the diagnosis was revised to neuroendocrine carcinoma (NEC), small cell type. Conclusion: Neuroendocrine tumors/NEC of the gallbladder are uncommon and clinically and surgically indistinguishable from carcinoma of the gallbladder. Patients usually present with the common gallbladder symptomatology. This tumor has a bad prognosis and it is essential that the correct diagnosis be made on radiographic and histopathological grounds with immunohistochemical confirmation.