Idiopathic retroperitoneal fibrosis.

This report presents the first autopsy case in Japan of idiopathic retroperitoneal fibrosis which had developed in a 71-year-old man. The clinical course was of extremely long duration of more than 10 years. Malignancy was suspected on biopsy, and at one stage chylous ascites developed. The cause of this retroperitoneal fibrosis could not be determined, but it is considered that the vicious circle of inflammatory processes such as cellulitis and lymphangitis in the retroperitoneum and lymphedema as well as lymphorrhage attributable to mechanical lymphatic obstruction brought about the retroperitoneal fibrosis.