Large Cell Neuroendocrine Carcinoma of the Gallbladder: Where Survival Is a Rare Entity - Case Report and Review of the Literature.

Introduction: Carcinoma of the gallbladder is extremely rare, papillary adenocarcinoma comprises 90% of these cases. Although neuroendocrine neoplasms (NENs) comprise 0.5% of the cases of gallbladder cancer, the incidence is rising. NEN is classified into a well-differentiated neuroendocrine tumor and poorly differentiated neuroendocrine cancer (NEC). Histologically, NEC is small-cell or large-cell carcinoma. We present the extremely rare case, 15th in the literature to be precise, of large cell neuroendocrine carcinoma of the gallbladder. Case Presentation: A 72-year-old male presented to the emergency department with constipation and right upper quadrant pain for 3 months. Computed tomography scan of the abdomen demonstrated an ill-defined 7.2 × 4.9 cm hypodense lesion in the gallbladder fossa with extension into the liver. Histopathological and immunohistochemical analysis of the biopsy specimen confirmed the diagnosis of large cell neuroendocrine carcinoma of the gallbladder. He was started on palliative chemotherapy. Conclusion: The plethora of tumors present in the gallbladder necessitates a search for risk factors for gallbladder neoplasia, and underscores the need to more carefully examine the nature of "asymptomatic gallstones." Further studies may reveal subclasses of cholelithiasis, gallbladder morphology, or imaging to define which patients should be followed more carefully, and may clarify additional risk factors for cancer of the gallbladder.