[Idiopathic retroperitoneal fibrosis. Pitfalls and challenges--experience with two cases].

Retroperitoneal fibrosis is the chronic, nonspecific inflammation of the retroperitoneum. About 75% of the cases are idiopathic. The pathomechanism of the disorder is not clearly defined. Autoimmune inflammation and secondary fibrosis are the main suspected mechanisms against an unknown factor possibly related to atherosclerosis. Symptoms and laboratory parameters are nonspecific which make the diagnosis difficult. At the time of the diagnosis complications are often present. After the urological and surgical management of the complications, the aim of the medical treatment is immunosuppression. Corticosteroids are usually used for treatment, although the optimal dosage and the duration of the treatment are not known. After therapy cessation relapse may occur, requiring repeated steroid therapy or addition of steroid sparing drugs. Predicting factors for treatment response, corticosteroid demand or relapse are not known. Authors review the medical history of two patients with retroperitoneal fibrosis and discuss diagnostic difficulties of this disorder.