A 56-Year-Old Woman with Acute Cholecystitis and a Moynihan's Hump, or Caterpillar Configuration, of the Right Hepatic Artery Identified During Laparoscopic Cholecystectomy.

BACKGROUND When performing a cholecystectomy, several variations can be encountered by the surgeon. The "Moynihan's hump" or "caterpillar configuration" of the right hepatic artery are the terms used to describe a tortuous right hepatic artery running proximal or parallel to the cystic duct, resulting in a small or short cystic artery and occupying most of Calot's triangle. This report is of a 56-year-old woman with acute cholecystitis and a Moynihan's hump or caterpillar configuration identified at laparoscopic cholecystectomy. CASE REPORT A 56-year-old woman presented herself to the Emergency Department with abdominal pain in the right upper quadrant for a week, associated with nausea, vomiting, and abnormal warm and cold sensation. Acute cholecystitis was diagnosed with ultrasound, and a laparoscopic cholecystectomy using a 4-port technique was performed. During the dissection of Calot's triangle, a large pulsatile vessel forming a loop was found, which turned out to be the right hepatic artery. The anatomic variation that was observed during the procedure is called Moynihan's hump or caterpillar configuration of the right hepatic artery. The surgery was uneventful, and the patient was discharged the next day. CONCLUSIONS The Moynihan's hump or caterpillar configuration of the right hepatic artery is a rare anomaly, with an incidence reported to be between 1.3% and 13.3%. This report has shown that although a Moynihan's hump or caterpillar configuration of the right hepatic artery is rare, the surgeon should be aware of this anatomic anomaly when performing gallbladder surgery to prevent arterial damage and operative complications.