[A case of psoas abscess with ureteral stone].

A 62-year-old diabetic woman with right hydronephrosis was referred to our department, presenting right back pain and high fever. A ureteral stone with right hydronephrosis was pointed on DIP. Although the calculus was removed by extracorporeal shock wave lithotripsy, persistent high fever continued. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) revealed a mass in the retroperitoneal space. Purulent fluid with a negative cytology was acquired by percutaneous biopsy following ultrasonography-guided percutaneous drainage. The postoperative course was uneventful with antibiotic therapy.