Abstract
The mode of cancer cell extension along the intrahepatic bile duct was studied histopathologically in serial sections of surgical specimens taken from 53 patients with hilar bile duct cancer. Two modes of extension were observed, a mucosal type (M: n=18) and an adventitial type (A: n=35). In the M type, cancer cells prominently infiltrated the mucosal layer rather than the adventitia. In contrast, A type cancer cells extend conspicuously along the adventitia. As to the macroscopic or histological characteristics of the lesions showing M type tumor extension,88% of them were grossly papillary type and papillary adenocarcinoma accounted for 12 out of 16 lesions (75%). On the other hand, A type tumor extension was more common in the cases with grossly infiltrating type and tubular adenocarcinoma including 5 cases with poorly differentiated type. In the cases with tumor with A type extension pattern, positive rate of residual cancer at the resection margin was significantly higher than that of M type.
