Objective: The purpose of this study was to analyze the CT findings in 10 patients with abdominal actinomycosis to determine the appearance of lesions and the pattern of spread of the disease.
Materials and methods: We retrospectively reviewed the CT findings in 10 patients with pathologically proved actinomycosis. Involved areas were the pelvis (n = 4), greater omentum (n = 3), liver (n = 2), and kidney (n = 1). Contrast-enhanced (oral and IV) CT scans were available in all patients. Unenhanced CT scans were also available in six patients.
Results: CT scans showed mostly solid masses with focal areas of diminished attenuation in seven patients and mostly cystic masses with thickened walls in three. CT findings confirmed the infiltrative nature of the disease, showing its tendency to invade across tissue planes and boundaries. Dense inhomogeneous contrast enhancement in the walls or solid components of masses was seen in eight patients. Minimal lymphadenopathy was seen in only two patients.
Conclusion: Although nonspecific, actinomycosis should be included in the differential diagnosis when CT scans show an infiltrative mass with unusual aggressiveness and dense inhomogeneous contrast enhancement, especially in patients with fever, leukocytosis, or long-term use of intrauterine contraceptive devices.