Early carcinoma of the extrahepatic bile duct.

This study attempts to define early carcinoma of the extrahepatic bile duct through a study of 11 patients whose carcinomatous invasion did not extend to the outer layer of the bile duct. The patients were divided into the following 3 groups, namely; a mucosa group comprised of 3 patients, a fibromuscular layer group comprised of 5 patients, and an adventitia group comprised of 3 patients. None of the patients had any lymphnode metastases. Histological characteristics were determined according to infiltrative growth (INF alpha, beta, gamma), lymphatic invasion (ly), venous invasion (v) and perineural invasion (pn). In the mucosa group, INF alpha was observed in 2 patients, while ly, v, and pn factors were all negative. In the fibromuscular layer group, INF beta was seen in 3 patients, ly was positive in 2 patients, while v, and pn factors were negative in all patients. In the adventitia group, INF gamma was found in 2 patients, and ly, v, and pn factors were positive in all patients except for 1 in whom v was negative. Death from recurrence occurred in all the adventitia group patients and in 1 other patient. Early carcinoma of the extrahepatic bile duct could therefore be defined at present, as being carcinoma confined to within the mucosa and fibromuscular layer.