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Hepatobiliary and pancreatic: Mucin‐hypersecreting neoplasms of the bile duct

Although mucin production by neoplasms is common, most of the mucin is retained within tumor cells or in small cysts. Mucobilia is a rare condition where hepatic or biliary neoplasms secrete large amounts of mucin into intrahepatic and extrahepatic bile ducts. This may cause or aggravate obstructive jaundice and occasionally results in cholangitis. It may also result in an unusual appearance at duodenal endoscopy where the ampulla of Vater is dilated by mucinous material; an appearance that may also occur with mucin-hypersecreting tumors of the pancreas. The causes of mucobilia include liver metastases, usually from primary colorectal cancers, and a variety of benign and malignant biliary neoplasms including biliary papillomatosis, cystadenomas, cystadenocarcinomas and cholangiocarcinomas. Most patients have either liver metastases or cholangiocarcinoma. In the latter disorder, mucinhypersecretion has been reported in up to 12% of cases and has been associated with a better prognosis, particularly after surgery. The outcome of investigations in a 96-year-old lady with abnormal liver function tests are shown in Figs 1,2. At the time of endoscopic retrograde cholangiopancreatography, duodenal endoscopy revealed a villous neoplasm involving the ampulla and extending into the duodenum (Fig. 1). Biopsies showed dysplastic villous epithelium. The cholangiogram revealed vague filling-defects within a dilated bile duct and a choledochoduodenal fistula. Mucus was aspirated from the biliary system. A computed tomography scan revealed dilated intrahepatic ducts with irregular thickening of the bile duct wall including probable cystic change (Fig. 2). The most likely diagnosis was biliary papillomatosis.