Cryptosporidiosis of the biliary tract in AIDS.

Cryptosporidiosis of the biliary system was studied retrospectively in 13 patients with acquired immunodeficiency syndrome (AIDS). The diagnosis was made by means of histologic examination (n = 9) or imaging studies and the presence of intestinal cryptosporidiosis (n = 4). Imaging studies were done in 10 patients. Ultrasound (US) and computed tomography (CT) showed dilatation of the biliary ducts, some with wall thickening, thickening of the gallbladder wall and pericholecystic fluid. Cholangiograms showed attenuation and pruning of the intrahepatic bile ducts, some with beading and dilatation of the common bile duct. Three patients had papillary stenosis. Numerous Cryptosporidium organisms were found in three resected gallbladders and in the biliary ducts of seven patients in whom autopsy was performed, accompanied by an exuberant inflammatory response. Correlation of the radiologic and pathologic findings establishes a direct etiologic role of Cryptosporidium as one of the major infectious agents in cholangitis associated with AIDS.