Follicular Cholecystitis: A Case Report Highlighting the Diagnostic Challenges and Management Implications.

Follicular cholecystitis (FC), a rare benign entity, represents <2% of cholecystectomies. We present imaging findings and immunohistochemistry used for diagnosis in an 82-year-old Thai female presenting with persistent colicky biliary pain. Upper abdomen magnetic resonance imaging revealed a gallstone and mild asymmetric gallbladder wall thickening. Diagnosed with symptomatic gallstones, she underwent laparoscopic cholecystectomy. Gross pathology indicated multiple nodules (0.1-0.5 cm) at the gallbladder fundus. Histopathological examination revealed transmural nodular lymphoid proliferation, suggesting a lymphoproliferative disorder or lymphoma. Subsequent immunohistochemistry led to a FC diagnosis. FC presents a significant diagnostic challenge and requires accurate pathological diagnosis to avoid unnecessary cancer treatments.