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Clinical presentation
A 67-year-old woman presented with paroxysmal epigastric pain for 3 months, without jaundice. She gave a history of cholecystectomy. Physical examination and blood tests were unremarkable. Magnetic resonance cholangiopancreatography showed cystic dilatation of the common bile duct (CBD), intrahepatic and extrahepatic bile duct dilatation and suspicious intrahepatic bile duct stones (figure 1). CT scan showed intrahepatic and extrahepatic bile duct dilatation and multiple intrahepatic bile duct stones (figure 2).
Magnetic resonance cholangiopancreatography showed cystic dilatation of the common bile duct, intrahepatic and extrahepatic bile duct dilatation and suspicious intrahepatic bile duct stones.
CT scan showed intrahepatic and extrahepatic bile duct dilatation and multiple intrahepatic bile duct stones.
Question
What is the most likely diagnosis in this case?
Answer
Endoscopic retrograde cholangiopancreatography showed dilatation of the CBD (24 mm), amorphous filling defects (figure 3) and a fish-eye sign with much mucus flowing out (figure 4). Cholangiopancreatoscopy showed that the multiple tiny mural nodules involved only the CBD, and mucin clots along with mucus formed the aforesaid filling defects (online supplementary video 1 and 2). Biopsy results proved intestinal-type intraductal papillary mucinous neoplasm (IPMN) with low-grade intraepithelial neoplasia (figure 5).
Supplemental material
Endoscopic retrograde cholangiopancreatography showed dilatation of the common bile duct and amorphous filling defects.
A fish-eye sign with much mucus flowing out.
Intestinal-type intraductal papillary mucinous neoplasm with low-grade intraepithelial neoplasia (H&E, magnification × 200).
The causes of biliary dilatation include biliary obstruction secondary to biliary stone, tumour and stricture; cholecystectomy, pancreaticobiliary maljunction, congenital choledochal cyst and so on. In this case, biliary dilatation was caused by mucus accumulation from IPMN of the bile duct (IPMN-B), and intrahepatic biliary stones might be associated with IPMN-B.1 2
Similar to IPMN of the pancreas, IPMN-B displays mucin-secreting papillary and/or cystic lesions, and can involve intrahepatic and extrahepatic biliary tracts.3 4 However, IPMN-B is rarer and shows a higher tendency to malignant transformation, and warrants more radical surgical treatment.1 4 5 Therefore, as a special subtype of biliary tumour,2 5 IPMN-B should not be ignored in the differential diagnosis of biliary dilatation.
Supplemental material
Footnotes
PP, S-Z and SW are co-first authors.
35 ZL and YB are co-corresponding authors.
Contributors YB was the guarantor of the overall content of the manuscript. ZL planned the study. PP and S-bZ collected the clinical data of the patient. PP and SW drawed up the manuscript. ZL submitted the manuscript.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Obtained.