We examined histologically the bile duct lesions from 53 patients with end-stage
primary sclerosing cholangitis (PSC) and compared them with similar lesions found in 25 surgically excised
carcinomas of the extrahepatic bile ducts not associated with PSC. Of the 53 cases of PSC, 50 bile ducts were obtained at
liver transplantation, two common bile ducts were segmentally resected for almost complete obstruction, and the entire extrahepatic biliary tract of another case was obtained at autopsy. Twenty bile ducts from patients who died without evidence of
biliary tract disease served as controls. A modest increase in the number of intramural glands (mild
hyperplasia) was noted in 13 cases (24.5%) of PSC. A marked increase in the number of intramural glands (florid
hyperplasia) was found in 14 cases (26.4%) of PSC. In one case of florid
hyperplasia, there was perineural and intraneural invasion of benign hyperplastic glands, which still maintained their lobular pattern. All cases of florid
hyperplasia of intramural glands were accompanied by extensive
fibrosis and marked nerve proliferation. Three of 24 (12.5%) invasive
adenocarcinomas of the extrahepatic bile ducts showed mild
hyperplasia of intramural glands without excessive nerve proliferation. Four invasive
adenocarcinomas and one in situ
carcinoma of the extrahepatic bile ducts showed florid
hyperplasia of intramural glands (16%). The hyperplastic intramural glands were p53 negative and had low proliferative activity as measured by the low MIB-1 labeling index. In contrast, both in situ and invasive
carcinoma expressed p53
protein and had a high MIB-1 labeling index. Focal high-grade dysplasia was found in one case of PSC (1.8%) and a small invasive
adenocarcinoma in another (1.8%).
Hyperplasia of intramural glands of the extrahepatic bile ducts is a reactive process that lacks specificity and is part of the morphologic spectrum of end-stage PSC. The incidence of dysplasia in PSC is low. Small invasive
adenocarcinomas may be incidentally found in end-stage PSC, and detecting their presence before
liver transplantation may be impossible.