Pancreatic Heterotopia in the Biliary Cyst Wall of a Pregnant Patient and Literature Review

Abstract

Pancreatic heterotopia is the presence of pancreatic tissue in a different anatomical location with no connection to the main pancreas. The most common locations in the gastrointestinal system are duodenum, stomach, and Meckel diverticulum. However, it is quite rare in the hepatobiliary system. Here we present a patient with pancreatic heterotopia who we treated with left hemihepatectomy and extrahepatic bile duct resection for Todani type 4a bile duct cyst. Heterotopic pancreatic tissue was present in dilated cystic bile ducts on pathological examination. A 22-year-old 26-week pregnant patient presented to the emergency department with right upper quadrant pain. There was massive dilatation of the left lobe bile ducts and common bile duct, and multiple stones were observed distal to the common bile duct. The patient was hospitalized for definitive surgical treatment 4 months after giving birth. The patient underwent left hemihepatectomy, extrahepatic bile duct resection, and hepaticojejunostomy. The postoperative course was uneventful. Pathological examination of the specimen showed heterotopic pancreatic tissues in the wall of the dilated cystic intrahepatic and extrahepatic bile ducts. One of the most accepted hypotheses in the etiology of biliary tract cysts involves the abnormal union of the pancreatic duct and common bile duct. This lesion is unique in the absence of pancreaticobiliary junction anomaly. We think that cystic dilation of intrahepatic and extrahepatic bile ducts is likely secondary to recurrent inflammation due to the release of digestive enzymes by heterotopic pancreatic tissue in the biliary tract. It is also the first example in the literature diagnosed during pregnancy.