High-Grade Neuroendocrine Tumor of the Gallbladder in a Young Female: A Rare Case Report and Literature Review

Neuroendocrine tumors (NET) of the gallbladder represent an exceedingly rare entity, accounting for approximately 0.2% of all NETs and 2% of gallbladder malignancies. The authors present the case of a 27-year-old woman who presented with a 1-month history of upper abdominal pain and vomiting. Contrast-enhanced CT scan revealed a large gallbladder mass with homogeneous enhancement and extensive lymphadenopathy. Histopathological examination and immunohistochemistry confirmed a high-grade (Grade 3) NET with a Ki-67 proliferation index of 90%. This case highlights the diagnostic challenges associated with these rare tumours, emphasizing the critical role of multimodal diagnostic approaches, including radiological imaging, histopathology, and immunohistochemistry. The authors provide a comprehensive review of the literature on gallbladder NETs, discussing their epidemiology, pathogenesis, clinical presentation, diagnostic workup, treatment strategies, and prognostic factors. Early recognition and appropriate management of these aggressive tumors are crucial, as high-grade gallbladder NETs are associated with poor prognosis and high mortality rates.