Splenic Involvement in Disseminated Mycobacterium avium-intracellulare Infection: Magnetic Resonance Imaging Findings

We report the imaging findings of a patient with disseminated Mycobacterium avium-intracellulare complex presenting with multiple splenic lesions incompletely characterized on computed tomography in whom magnetic resonance imaging helped narrow the differential diagnosis. We discuss the magnetic resonance imaging findings suggesting the diagnosis, including the presence of focal susceptibility artifact within the lesions (ie, signal drop on T1 in-phase imaging), marked hypointensity on diffusion-weighted imaging, and faint progressive peripheral enhancement after contrast administration. We provide pathologic correlation to explain these imaging characteristics and a review of the literature of imaging characteristics in splenic involvement of M. avium-intracellulare complex infection.