[A case of infected renal cyst extending to leg abscess].

A 45-year-old woman was referred to our hospital with the chief complaint of left flank pain, left leg pain and loss of appetite. Computed tomography scan and magnetic resonance imaging demonstrated a large cystic mass in the left kidney, which we diagnosed as an infected renal cyst. Under ultrasonic guidance, percutaneous puncture and drainage of the renal cyst were performed. After her leg pain worsened, computed tomography revealed abscesses in the left leg, suggesting an infected renal cyst extending to the leg through the obturator foramen. Under general anesthesia, incision and drainage were performed. Cultures from the cyst and abscess fluid showed Klebsiella pneumoniae. Our case is the 82nd case of an infected renal cyst in the Japanese literature.