Magnetic resonance imaging of actinomycosis presenting as pelvic malignancy

Pelvic actinomycosis is associated with long-standing use of an intrauterin e 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 presen t a case of pelvic actinomycosis with tube-ovarian abscess in which magneti c resonance imaging demonstrated lower signal intensity tissue on T-2 weigh ted sequences than would be typical for pelvic malignancy or infection and was useful in confirming regression of pelvic disease in response to antibi otic therapy.