Abstract
Pelvic actinomycosis is an uncommon infectious disease. It induces a chronic, suppurative illness characterized by an infiltrative and granulomatous response and, thus, the clinical and radiologic findings may mimic other inflammatory and neoplastic conditions. A 56-year-old female with a long-standing intrauterine device was diagnosed with pelvic actinomycosis manifesting as a large uterine mass with locally infiltrative spread into surrounding tissue that mimicked uterine malignancy. Actinomyces israelii infection was confirmed with a surgical specimen, and the patient was treated with antibiotic medication. Pelvic actinomycosis must be included in the differential diagnoses of patients with an infiltrative pelvic mass extending across tissue planes or in patients with findings of multiple microabscesses, particularly in a patient with an intrauterine device, even the lesion primarily involves the uterus.