Anatomical Trickery in Acute Cholecystitis: Very Low Cystic Duct Insertion Near the Ampulla of Vater.

Anatomical variations of the cystic duct are relatively common; however, insertion at or near the ampulla of Vater is exceptionally rare and carries significant implications for surgical and endoscopic management. We report a case of a 69-year-old male who presented with acute gangrenous cholecystitis and biliary sepsis. In our setting, magnetic resonance cholangiopancreatography (MRCP) is not routinely performed for acute cholecystitis, being reserved for stable patients with obstructive liver function tests or suspected choledocholithiasis. Most patients are adequately assessed using ultrasound, and when indicated, computed tomography. Given the patient's instability and urgent need for source control, preoperative MRCP was not obtained. Intraoperative cholangiography (IOC) was undertaken during laparoscopic cholecystectomy and demonstrated a very low cystic duct insertion at the level of ampulla of Vater. The operation proceeded with careful dissection to achieve the critical view of safety (CVS). Postoperative MRCP, arranged after the acute episode, confirmed the IOC findings. The patient had an uncomplicated recovery and was discharged on postoperative day five. Very low cystic duct insertion increases the risk of bile duct injury and may cause technical challenges during both laparoscopic cholecystectomy and endoscopic retrograde cholangiopancreatography (ERCP). This case highlights the importance of intraoperative biliary mapping in complex or emergency gallbladder surgery, especially when preoperative imaging is not feasible, not indicated, or not accessible, and reinforces the role of IOC in safely identifying rare anatomical variants.