Extrahepatic biliary atresia with cartilaginous metaplasia in the gallbladder remnants.

Extrahepatic biliary atresia (EBA) is a chronic inflammatory process leading to fibrous obliteration of the biliary tree. Cartilaginous metaplasia within the remaining walls of the biliary main ducts in EBA has been reported once, although as cartilage heterotopia. A similar finding is presented here, but in the gallbladder of an infant with the full-blown manifestations of EBA; it is proposed that the alteration results from metaplasia of local connective tissue. Also of note is the complete disappearance of smooth muscle cells in the walls of the biliary tree in EBA, a fact which seems to be missing in the description of the pathology in these cases.