Primary Neuroendocrine Tumor of Gallbladder: A Mystery Solved by Histopathology

A BSTRACT Gallbladder neuroendocrine tumors account for just 0.2% of all neuroendocrine tumors, making them a very uncommon type of cancer. Gallbladder neuroendocrine tumors are typically asymptomatic; most cases have been documented as unintentional specimen findings that were removed because of secondary symptoms such as chronic cholecystitis. The primary method of diagnosing gallbladder-neuroendocrine tumors (GB-NETs) is histological analysis of the gallbladder, since biliary pathology is complicated to diagnose with only imaging. Here, we discuss a case of a 62-year-old man, clinically and radiologically suspected gallbladder neoplasm. Fine Needle Aspiration Cytology (FNAC) was performed which showed suspected adenocarcinoma. We diagnosed it as a well-differentiated grade III primary neuroendocrine tumor of the gallbladder after histopathology and immunohistochemical examination. It is essential to identify the rare entity due to its worse prognosis compared with gallbladder adenocarcinoma.