Diffuse Xanthogranulomatous Cholecystitis: Master of Disguise.

A 67-year-old woman presented with clinical symptoms, radiological findings, and preoperative work-up highly suggestive of advanced stage IV carcinoma of the gallbladder (CG). An extended cholecystectomy with the excision of adjacent liver segments and loco-regional lymphadenectomy was performed. Final pathology results revealed diffuse xanthogranulomatous cholecystitis (XG) with ruptured Rokitansky-Aschoff sinuses with tumor-resembling adenomyosis without atypical or malignant cells. There was a reactive inflammatory and fatty degeneration of the adjacent hepatic tissue and a nonspecific inflammatory reaction of the enlarged periportal lymph nodes. The main concern in the management of patients with mass-forming XG is that this benign condition shares strikingly similar clinical, imaging, biochemical, and intraoperative features with advanced CG, which has one of the poorest overall survival rates. Misdiagnosis is not uncommon, which causes significant distress for patients and their families and, in some cases, may result in erroneous treatment. Although the presence of some preoperative imaging findings and/or intraoperative frozen section biopsies may be helpful in suspecting XG, definitive diagnosis is usually delayed until the final pathology result that may come as a surprise. Increasing awareness of this rare, insidious disease will contribute to a better understanding of its biology and natural history and, eventually, help improve management.