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When bile duct strictures are identified at endoscopic retrograde cholangiopancreatography (ERCP), the distinction between benign and malignant can be challenging.
A previously fit and well woman of 88 was referred for investigation of painless jaundice. There was no history of fevers, with or without rigors. She had not lost any weight and was teetotal. She had no relevant medical history and was not on any medications. General and systemic examination was unremarkable except for deep jaundice. Biochemically the picture was of obstructive jaundice (bilirubin 89 μmol/L, alkaline phosphatase 470 iu/L, alanine aminotransferase 42 iu/L, albumin 31 g/L). Abdominal ultrasound showed dilated intrahepatic ducts, dilatation of the common hepatic duct and a proximal common bile duct (CBD) 1.5 cm in diameter. Gallstones or bile duct stones were not seen and the pancreas was normal. An ERCP showed several calculi in the CBD. A sphincterotomy followed by a balloon trawl cleared all the stones. Her jaundice resolved and liver function tests became normal. Twelve months later the symptoms had returned and ultrasound findings were similar. At ERCP the CBD could not be cannulated; she was treated with intravenous antibiotics and her jaundice improved. A CT scan of the abdomen showed, in addition to dilated ducts, a short stricture at the lower CBD. On percutaneous transhepatic cholangiography multiple filling defects were seen in the common hepatic duct extending proximally into the intrahepatic ducts with narrowing of the distal CBD. The appearances were interpreted as extensive cholangiocarcinoma. Contrast was seen to flow into the duodenum (Figure 1). In view of the extent of disease and her age no further investigation or therapeutic action was planned. Over the next 2 years she had repeated episodes of jaundice which settled with intravenous antibiotics. As she continued to be well between admissions, the diagnosis of cholangiocarcinoma was doubted. A repeat ERCP showed a long segment of stricture in the mid CBD with filling of an apparent single duct superior to the stricture. An irregular tract was also noted emptying laterally into the hepatic flexure, suggestive of a biliary-colic fistula (Figure 2). A stent was placed across the stricture, which sealed the fistula. Seemingly, recurrent inflammation secondary to calculous disease had led to perforation into the colon.
Benign conditions that can mimic cholangiocarcinoma include localized strictures in primary sclerosing cholangitis, iatrogenic strictures1, suture granuloma2, amputation neuroma of the cystic duct3 and Mirizzi's syndrome with a high CA 19-94. Laboratory data are not always helpful in distinguishing benign from malignant. Cytological examination of bile obtained during cholangiography reveals typical malignant cells in only 25-50% of cholangiocarcinoma cases5,6. Serum tumour markers are of limited value. Carcinoembryonic antigen (CEA) is expressed in some bile duct cancer cells and an increased level in bile may be informative7. Fibronectin is another candidate marker in bile8.
Although the diagnosis of cholangiocarcinoma should be thought of in elderly patients, further investigations—particularly bile cytology along with bile CEA levels, brushings and dual phase CT or MR sequences—should be obtained before a confident diagnosis is made. If surgery is contraindicated by comorbidity, a biliary stent should be inserted during ERCP or percutaneous transhepatic cholangiography. A fistula from bile duct to colon has been reported only once before with bile duct calculi though it is a recognized complication of gallbladder cancer and of highly invasive bowel cancers.