Cholestasis: surgical pathology, mechanisms, and new concepts.

This report has attempted to describe concisely the main diagnostic morphological features seen in cholestasis and to explain them mechanistically. The number of clinical conditions in which cholestasis can be found is extremely large and varied, so that no single mechanism explains all cases; in fact, multiple factors are operative in frequent instances. Currently used terminology and concepts are explained. The report is not intended to be comprehensive but is intended to deal with the most common types of cholestasis and with those in which recent advances in new knowledge have been made. The first step, in all cases, is to try to localize the site of obstruction, so an anatomic classification of cholestasis is offered as being most helpful, both in diagnostic work and in consideration of the mechanisms involved. In selecting the cases for special consideration, a personal bias is introduced but is unavoidable. The discussion of canalicular cholestasis is particularly abridged because many of the mechanisms proposed, including the two that are briefly discussed, are still the subject of ongoing investigation but are included because they are illustrative of current concepts in the field.