[A case of early extrahepatic bile duct cancer showing diffuse growth].

A 74-year-old woman visited our hospital for a health checkup, and liver dysfunction and cholangiectasis were detected. Further examinations revealed a protruding lesion spreading diffusely from the upper to the lower extra-hepatic bile duct. On a diagnosis of extra-hepatic bile duct cancer, the patient underwent pancreato-duodenectomy with preservation of the pyloric ring. Small papillary denticulate lesions, forming papillary adenocarcinoma, was scattered over a flat granular lesion of atypical hyperplasia. This morphological pattern is rare, and suggests that the cancer cells may have derived from atypical hyperplastic epithelium.