Paucity of interlobular bile ducts.

Paucity of interlobular bile ducts (PIBD) is defined as the reduction in the number of interlobular bile ducts. Paucity could be defined using the ratio of the number of portal tracts devoid of bile duct to the total number of portal tracts. At least 10 complete portal areas must be examined. In the past, only wedge biopsies could provide such samples, but now it can be achieved with needle biopsy. Usually, two types of PIBD, syndromatic and nonsyndromatic, are considered. In the syndromatic type, paucity is a major feature of the disease. In the nonsyndromatic type, paucity is only a part of the disease, as in peroxisomal disorders or alpha 1-antitrypsine (A1AT) deficiency, and is an inconstant finding. Opacification of the intrahepatic bile ducts in infants with nonsyndromatic paucity with no associated disorder demonstrates sclerosing cholangitis in at least half of patients in whom the diagnosis of "idiopathic paucity" would have been made a few years ago. The remaining patients must be considered as waiting for the identification of new disorders associated with paucity.