In a 58-year-old woman, a cystic mass at the ileocecal region communicated with the loosened hip prosthesis 20 years after total hip arthroplasty (THA). The preoperative arthrogram of the hip and the intraoperative cystogram suggested a one-way communication from the hip to the cystic mass. The mass was diagnosed as an iliopsoas bursitis distended by the influx of the synovial fluid from the loosened THA.