Papillary adenoma of the distal common bile duct

A 73-year-old man with a papillary adenoma located in the distal common bil e duct is reported. He underwent pylorus-preserving pancreatoduodenectomy. The lesion in the common bile duct featured papillary proliferation of the epithelium and fibrous elements with diffuse infiltration by inflammatory c ells. Positive staining for MIB-1 (Ki-67) and p53 was identified in the nuc lei of the proliferative epithelium. These findings suggested the malignant potential of this lesion. Further progress in imaging diagnostic technique s should increase the frequency with which such lesions are discovered. Eve n now, if mural irregularities and defects are found in the extrahepatic bi liary system, especially the distal common bile duct, the possibility of su ch borderline biliary adenoma should be taken into consideration when makin g a diagnosis.