Leg edema due to a mass in the pelvis after a large-diameter metal-on-metal total hip arthroplasty.

We report the case of a patient with leg edema after large-diameter metal-on-metal total hip arthroplasty. At 1 year and 2 months after primary left large-diameter metal-on-metal total hip arthroplasty, the patient complained of left leg edema. At first, we suspected deep venous thrombosis. However, deep venous thrombosis was not detected by venous ultrasonographic examination. Computed tomography imaging revealed a mass in front of the iliac fossa. The mass compressed the left iliac artery and vein. We therefore believed that this lesion was the cause of the leg edema and performed resection of the mass. The resected mass consisted of necrotic tissue infiltrating inflammation cells, so it was diagnosed as pseudotumor. Unilateral leg edema disappeared gradually after the resection.