[Idiopathic retroperitoneal fibrosis: a case report without increased levels of acute-phase reactants. Noninvasive diagnosis and treatment].

We report a case of benign idiopathic retroperitoneal fibrosis in a 39-year-old male, who was successfully treated with immunosuppressive drugs only. Advances in imaging techniques, especially in magnetic resonance imaging, often permit an accurate diagnosis in retroperitoneal fibrosis, avoiding open biopsy or biopsy by means of image-guided techniques. In addition, the modern medical approach with immunosuppressive drugs is based on evidence of disease regression following the medical therapy and is frequently effective. Hence, it is possible to avoid conventional surgery or laparoscopy. In the present case the response to immunosuppressive treatment was objectively assessed by means of enhanced computed tomography, magnetic resonance and nuclear medicine (Ga-67), showing an important decrease in the extent of the disease at follow-up. Our case shows the important role of the specialist in Internal Medicine in the treatment of this uncommon connective tissue disease.