When acute cholecystitis is not what it seems: torsion of a free-floating gallbladder.

Free-floating gallbladder is a rare anatomic variant characterized by excessive mobility due to an elongated mesentery, predisposing it to torsion and vascular compromise. When torsion occurs, obstruction of the cystic duct and artery may rapidly progress to ischemia, necrosis, and gangrene, constituting a surgical emergency. Preoperative diagnosis is challenging because clinical, laboratory, and imaging findings often mimic uncomplicated acute cholecystitis. We report the case of an 87-year-old male with liver cirrhosis presenting with diffuse abdominal pain and elevated inflammatory markers. Ultrasonography and computed tomographic angiography were consistent with acute cholecystitis. However, laparoscopic exploration revealed a torsioned, necrotic, gangrenous free-floating gallbladder. Laparoscopic cholecystectomy was successfully performed, and recovery was uneventful. This case highlights the diagnostic limitations of imaging in rare anatomic variations and underscores the importance of early surgical intervention and intraoperative vigilance.