CT findings of abdominal actinomycosis

ABSTRACT

Actinomycosis still poses a problem for correct clinical and radiologic diagnosis. We retrospectively analyzed CT findings in 7 patients with pathologically proven abdominal actinomycosis. Involved areas were the pelvis (n=3), greater omentum (n=2), liver (n=1), and kidney (n=1). CT confirmed the infiltrative nature of the disease with a tendency to invade across tissue plane and boundary. Five of seven cases were predominantly solid mass (pseudotumor) with focal low-attenuation areas while two were predominantly cystic mass with thickened wall. Contrast-enhanced CT showed dense, inhomogeneous contrast enhancement in the wall and/ or solid components of the masses in five. Minimal lymphadenopathy was noted in one case. CT is useful in demonstrating the extent and characteristics of this disease. Despite nonspecific findings, actinomycosis should be included in the differential consideration when CT shows an infiltrative mass with unusual aggressiveness and dense inhomogeneous contrast enhancement in patients with fever, leukocytosis, or long-term use of intrauterine contraceptive devices.