Gallbladder neuroendocrine neoplasms: a review.

Gallbladder neuroendocrine neoplasms (GB-NENs) are rare, aggressive tumors that represent a unique subset of biliary tract malignancies. The etiology remains poorly understood, with hypotheses suggesting origins from metaplasia induced by chronic inflammation or differentiation from adenocarcinoma. Most GB-NENs present with vague or absent symptoms, leading to frequent incidental detection during cholecystectomy or at advanced stages with distant metastases. Diagnosis is challenging due to the lack of specific clinical and imaging features; thus, histopathological evaluation with immunohistochemical staining for neuroendocrine markers is necessary. Treatment is not standardized; it typically follows strategies for gallbladder adenocarcinoma and other neuroendocrine neoplasms. Surgical resection is the mainstay for localized disease and has the greatest impact on survival. This review provides an updated synthesis of the epidemiology, pathogenesis, clinicopathological features, diagnostic criteria, and evolving management of GB-NENs, highlighting ongoing research in this challenging but increasingly recognized disease entity.