From June, 1987 to November, 1989, 11 patients with malignant bile duct stenosis, which was later confirmed by surgery or autopsy, were examined by percutaneous transhepatic cholangioscopy (PTCS) and by an endoscopic biopsy. The endoscopic findings obtained with the usual observation methods and methylene blue staining and the histological findings of the biopsy specimens were compared. A fine vascular proliferation was seen in all of the patients and a granular appearance was noted in patients with carcinoma of the major papilla. The papillary appearance was noted in one case each of pancreatic carcinoma, bile duct carcinoma and carcinoma of the major papilla. Marginal protrusion was not noted in patients with pancreatic carcinoma. A distorted narrow segment was seen only in cases of pancreatic carcinoma. The presence of a granular appearance indicated that the carcinoma was exposed on the surface. A high degree of fine vascular proliferation and a papillary appearance tended to indicate a carcinoma which invaded mainly into the fibromuscular layer without invasion of the mucosa. The methylene blue staining method was simple and effective for better visualization of the surface structure of the abnormal area, normal mucosa and the border zone.

Twenty colorectal sessile tumors, with nodular surface aggregates, were endoscopically resected in 20 patients. Among 17 tumors less than 19 mm in diameter, 16 were completely resected in one session and one required piecemeal resection to achieve complete removal. All three lesions measuring over 30 mm were resected piecemeal, and one of these lesions was concurrently heat‐probe treated. Thus, all lesions were completely resected endoscopically. Histologically, tubular adenoma was identified in nine resected specimens, tubulovillous adenoma in eight, serrated adenoma in one, and carcinoma in adenoma in two. None of the malignant lesions had invaded the submucosa. Adenomas showing severe atypia and carcinomas in adenomas accounted for 55% of all lesions. These findings indicate that endoscopic mucosal resection is the treatment of choice for sessile tumors with nodular surface aggregates; lesions which cannot be managed by this procedure should be surgically resected.

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