Primary Small Cell Neuroendocrine Carcinoma of the Gallbladder With Liver Metastases: Case Report and Narrative Review

ABSTRACT Background Primary small cell neuroendocrine carcinoma (SCNEC) of the gallbladder is exceedingly uncommon and highly malignant, typically presenting at an advanced stage with a poor prognosis. Due to its rarity and nonspecific clinical manifestations, timely diagnosis remains a major challenge in clinical practice. Case Presentation An 80‐year‐old woman presented with a 10‐day history of intermittent epigastric pain radiating to the back. Abdominal ultrasound and contrast‐enhanced CT revealed a gallbladder fundus mass invading adjacent hepatic segments, accompanied by multiple hepatic lesions. Ultrasound‐guided biopsy of a hepatic lesion confirmed SCNEC by histopathology and immunohistochemistry. Conclusions Primary gallbladder SCNEC is a rare, high‐grade malignancy with rapid progression and poor prognosis. This case highlights the importance of early multimodal imaging evaluation and timely histopathologic confirmation. Early recognition and multidisciplinary care are pivotal to optimizing outcomes.