[Psoas abscess caused by nephrolithiasis with perirenal abscess complicated with pleural effusion]

Left pleural effusion was found in a 60-year-old woman in whom chest radiography performed during a physical check up revealed no abnormality. Abdominal CT scanning revealed an abscess in the left psoas muscle. The psoas abscess was eliminated temporarily by drainage under ultrasonographic guidance and by the administration of antibiotics, but recurred one month later. A stag-horn renal stone considered to have caused the psoas abscess by formation of a perirenal abscess was eliminated by left nephrectomy. It is suggested tentatively that the psoas abscess might have been the cause of the pleural effusion.