[Tubercular abscess of the psoas without associated spinal involvement. A case report]

Tuberculous psoas abscess outside of locoregional causes is uncommon and can cause a problem of differential diagnosis.

We report a case of unilateral tuberculous abscess of the psoas which first clinical and radiological features presented like a retroperitoneal tumor. Exploration laparotomy discovered a bulky abscess of the left psoas muscle. Bacteriologic and histologic evaluation confirmed the tuberculous origin. Radiological study of the spine did not show any signs of spondylodiscitis. Under antituberculosis treatment a crural collection occurred and a surgical drainage was performed. Five years later, there was a recurrence of a crural collection which responded well to antituberculosis treatment.

Tuberculous psoas abscess is usually secondary to spinal involvement, more uncommonly to digestive, urologic or genital tuberculosis. Primary abscess was rarely described and the pathogenesis remains unclear. Psoas contamination is supposed to be hematogenous or lymphatic in origin. Ultrasonography and computed tomography (CT) transformed the diagnosis and the therapeutic approach by percutaneous puncture and drainage.