Xanthogranulomatous Cholecystitis Presenting as Chronic Calculous Cholecystitis: A Diagnostic Challenge.

Xanthogranulomatous cholecystitis (XGC) is an uncommon benign inflammatory disease of the gallbladder characterized by destructive inflammatory changes, fibrosis, and infiltration of lipid-laden macrophages. Despite its benign nature, XGC can closely mimic gallbladder carcinoma (GBC) clinically, radiologically, and intraoperatively, posing a significant diagnostic challenge. We report the case of a 58-year-old female who presented with recurrent right upper quadrant pain for several months, aggravated by food intake and occasionally associated with nausea. There was no history of fever, jaundice, vomiting, or weight loss. Clinical examination revealed mild tenderness in the right hypochondrium without guarding or palpable mass. Laboratory investigations were within normal limits, and imaging findings were suggestive of chronic calculous cholecystitis. The patient underwent open cholecystectomy. Intraoperatively, the gallbladder was thick-walled with dense adhesions and contained a gallstone. Histopathological examination revealed mucosal ulceration, submucosal fibrosis, muscular hypertrophy, and transmural infiltration by foamy histiocytes with mixed inflammatory cells, confirming XGC. No evidence of malignancy was identified. This case highlights the diagnostic difficulty of differentiating XGC from GBC preoperatively. Histopathological examination remains the gold standard for definitive diagnosis.