Acute cholangitis due to a Type IV Mirizzi syndrome management strategy of a rare condition: a case report.

Introduction: Mirizzi syndrome (MS) is a rare complication of chronic cholelithiasis, resulting from an impacted gallstone in the cystic duct or gallbladder neck, leading to common hepatic duct obstruction. Advanced cases, such as Type IV, involve cholecystobiliary fistula formation, posing significant diagnostic and therapeutic challenges. Case Presentation: We report a case of a 69-year-old woman presenting with jaundice, fever, and right upper quadrant pain. Laboratory tests revealed cholestasis and hepatic cytolysis. Imaging, including ultrasonography computed tomography, and magnetic resonance imaging, confirmed Type IV MS with a cholecystobiliary fistula and large gallstones obstructing the bile duct. Due to the complexity of endoscopic treatment, an open surgical approach was performed. A cholecystotomy with stone extraction and T-tube drainage was undertaken. The postoperative course was uneventful, with normalization of liver function tests and no complications at 1-year follow-up. Discussion: MS remains a diagnostic challenge due to its variable presentation and resemblance to malignant biliary strictures. A multimodal imaging approach (ultrasonography magnetic resonance cholangiopancreatography, and endoscopic retrograde cholangiopancreatography) is essential for accurate classification and surgical planning. Treatment depends on disease severity, ranging from simple cholecystectomy to bilioenteric anastomosis in advanced cases. While laparoscopic management is possible, open surgery remains preferred in complex cases to reduce bile duct injury risk. Conclusion: Early recognition of MS, comprehensive imaging, and a multidisciplinary approach are critical for optimal management. This case highlights the importance of tailored surgical intervention in treating advanced MS effectively.