Acute cholangitis secondary to a common bile duct adenoma

We report a case of distal common bile duct adenoma presenting with acute cholangitis. A 47-year-old woman suffered from right upper abdominal pain with persistent fever for 4 days. Abdominal ultrasonography showed mild dilatation of common bile duct and bilateral intrahepatic ducts. Endoscopic retrograde cholangiopancreatography disclosed a fixed filling defect in the distal common bile duct. Transpapillary biopsy and brush cytology was performed after sphincterotomy. The biopsy specimen showed adenomatous change with dysplasia and negative stain for p53. No significant regional lymph node enlargement was found on computed tomography. The patient subsequently received exploratory laparotomy and sphincteroplasty with excision of the distal common bile duct tumor. Finally, the tumor was diagnosed as common bile duct tubular adenoma with moderate nuclear dysplasia. Postoperatively, the patient had an uneventful course and has been well at follow-up for 8 months. We encountered a rare case of common bile duct adenoma in which malignant change was hard to rule out. We propose that sphincterotomy with biopsy is crucial before operation and p53 immunohistochemical staining is valuable for determining whether or not malignant change occurs in this borderline tumor.