[Pyomyositis of iliopsoas muscle with infection of renal cyst: a case report].

We report a case of pyomyositis of iliopsoas muscle with infection of renal cyst. A 50-year-old woman was admitted to our hospital complaining of left lumbago, and we suspected that she had a left ureteral stone at first. Ultrasonogram and intravenous pyelography showed bilateral multilocular renal cyst and enlargement of the left iliopsoas muscle. Finally she was diagnosed with left pyomyositis of iliopsoas muscle with infection of renal cyst by ultrasonogram, computerized tomography scan and magnetic resonance imaging. She had no complaints after she had received antibiotic therapy for a week.