Repeated thrombophlebitis with pulmonary embolism in a 28-year-old female led to the discovery of a complex malformation of the inferior vena cava which required the insertion of a clip. Three years later, recurrence of phlebitis with appearance of bipolar aphthae, arthritis and a meningeal syndrome led to the diagnosis of Behçet disease. Despite various medications for this disorder and heparin or oral anticoagulant therapy, the thromboembolic disease remained active, accompany with new exacerbations of Behçet disease. Diminished plasma fibrinolytic activity was demonstrated, probably resulting from venous endothelial vascularitis, which aggravates the consequences of the preexisting vascular malformation.