DRAGOS PUIA, DANIELA RADULESCU, STEFAN GHEORGHINCA, FLAVIA LILIANA TURCU, ILEANA ADELA VACAROIU, CATALIN PRICOP SPONTANEOUS REMISSION OF RETROPERITONEAL FIBROSIS IN A PATIENT WITH INHERITED THROMBOPHILIA Retroperitoneal fibrosis (RPF) is a rare condition characterized by a diffuse or localized fibroblastic proliferation associated with chronic inflammation. RPF is generally idiopathic, but can also be secondary to the use of certain drugs, malignant diseases, infections, and surgery. Treatment of RPF aims to relieve ureteral obstruction and to induce disease regression, and includes the use of steroids combined or not with other immunosuppressive agents. We present the case of a 35-years old female with a medical history of transient ischemic stroke, myocardial infarction, miscarriage and inherited thrombophilia, who was diagnosed in our Department with idiopathic RPF. Due to the mentioned associated comorbidities, no immuno-active treatment could be initiated. After one year, MRI exam showed significant spontaneous decrease of RPF mass. Although an uncommon event, the spontaneous resolution of idiopathic RPF could encourage in some selected cases a conservative management. By our knowledge, no previously cases of spontaneously remitted RPF in patients with inherited thrombophilia have been reported.