Magnetic resonance imaging of actinomycosis presenting as pelvic malignancy

Pelvic actinomycosis is associated with long-standing use of an intrauterine contraceptive device and may present with clinical signs and symptoms of pelvic malignancy. Diagnostic imaging can confirm the presence of a pelvic mass and tissue infiltration but findings are often non-specific. We present a case of pelvic actinomycosis with tube-ovarian abscess in which magnetic resonance imaging demonstrated lower signal intensity tissue on T-2 weighted sequences than would be typical for pelvic malignancy or infection and was useful in confirming regression of pelvic disease in response to antibiotic therapy.