Caterpillar chronicles: adventuring through Moynihan’s legacy in laparoscopic cholecystectomy

Before the introduction of minimally invasive surgery, there was a heightened focus on studying anatomical variants and their frequency due to the increased risk of biliary tract injury and hemorrhagic and ischemic arterial injury. This was done through the "Culture for safe cholecystectomy (CSC)" proposed by Strasberg, which underscored the significance of standardizing these variants using the classifications of Blumgart and Michael. These classifications centered on the insertion site of the biliary duct and cystic artery (CA), respectively. A tortuous pattern of the right hepatic artery (RHA) resembling a caterpillar or a hump (caterpillar hump or Moynihan's hump) that runs proximal or parallel to the cystic duct and gallbladder is often associated with the presence of a short CA, posing a high risk of vascular injury. The tortuous RHA can form a single or double loop and pass posteriorly or anteriorly to the common hepatic duct, with the posterior presentation being the most common. This represents one of the most serious lesions described, despite its low frequency, with an incidence reported to be between 1.3% and 13.3%. We present a case of a 33 years old woman with acute cholecystitis and a Moynihan’s hump or caterpillar configuration of the RHA, which was identified during laparoscopic cholecystectomy.