The iliopsoas bursa is the largest bursa in the region of hip joint. It is unusual that these bursa become symptomatic. However the bursa can compress femoral vein, leading to lower extremity edema. A 58-year-old man was referred to our department for his unilateral leg edema which had been treated as deep vein thrombosis without any favorable response. Magnetic resonance angiography was performed, which demonstrated enlarged iliopsoas bursa compressing his femoral vein. Surgical removal of the bursa was performed. The postoperative course was uneventful, and the patient is free from symptoms with no evidence of recurrence.Key words: iliopsoas bursa, lower extremity edema, femoral vein compression extremity. He consulted our cardiologist and the ultrasound technique (US) was performed. This revealed the incompressibility of left femoral vein under compression with the probe, the presence of a slightly echogenic mass, and the lack of venous distension with a Valsalva maneuver. From these findings, he was diagnosed to have DVT and given anticoagulant therapy, which had no effect on his symptoms. So he was consulted to our department. His left lower extremity was swollen with a tender mass, 30 mm × 10 mm in diameter, localized at his left groin. The circumference of his thighs were 45 cm on the right and 50 cm on the left (Fig. 1A). He has not had any medical history related to his hip joint. We performed US again and computed tomographic (CT) scan. They showed cystic lesion compressing his left femoral vein laterally (Fig. 1B, C). Magnetic resonance angiography (MRA) was also performed, which clearly demonstrated cystic lesion connected to the iliopsoas muscle compressing femoral vein externally (Fig. 1D). From these findings, we diagnosed the enlarged iliopsoas bursa compressing his femoral vein as the cause of the edema of his left lower extremity, mimicking the symptoms of deep vein thrombosis. At operation, femoral vein was found to be surrounded by the bursa which was difficult to be resected completely. We opened the bursa which was filled with the viscous fluid (Fig. 2). After evacuation of fluid, we resected the bursa as completely as possible, leaving the region which adhered strictly to the venous wall. By this procedure, reexpansion of the compressed femoral vein was obtained. Postoperative course was uneventful. The edema resolved as indicated by the decrease of his left thigh circumference from 50 cm preoperatively to 47 cm postoperatively, and his symptoms completely disappeared. At 1-year follow-up he is free of symptoms with no evidence of recurrence.