[Renal actinomycosis: a case report]

This report describes the case of a 26-year-old patient hospitalized for spontaneous abdominal pain. Palpation during clinical examination demonstrated a mass in the right abdomino-pelvic cavity. Radiological examination visualized the presence of grains suggestive of actinmycosis. The patient responded favorably to antimicrobial therapy. Actinomyces israeli is a gram-positive anaerobic bacterium that can cause tumor-like lesions usually on the face and neck and more rarely on retroperitoneal structures. Because renal involvement can require nephrectomy, diagnosis of renal actinmycosis must be made during pre-operative work-up. Ultrasound-guided needle biopsy of the lesion can achieve diagnosis and avoid nephrectomy since medical treatment using antimicrobial therapy is effective.