[Pyonephrosis complicated by a pyogenic psoas abscess. Apropos of a case].

Psoas abscess of pyogenic origin developed secondary to renal infection in a patient with coralliform lithiasis, a favorable outcome being obtained after nephrectomy and drainage of abscess. Clinical diagnosis is difficult but ultrasound and CT scan imaging provide useful data. Other causes of pyogenic abscess are discussed, the most frequent origin being digestive disease.