Retroperitoneal Fibrosis with Intrinsic Ureteral Involvement

Abstract
Two cases of idiopathic retroperitoneal fibrosis are discribed. In both cases intrinsic involvement of the ureteral muscularis was found, which is in contradistinction to the classical description of ureteral encasement or compression by the process without actual invasion. Surgical procedures, in addition to ureterolysis, may be required.