Atypical mycobacteria in a patient with HIV and ITP.

A tentative diagnosis of HIV–immune thrombocytopenic purpura (ITP) was made. She was treated with antiretroviral medications, IVIG, and subsequently with steroids for 4 weeks without improvement. Rituximab was deemed unsafe because of her immunosuppressed status. After 6 weeks of platelet unresponsiveness, a bone marrow examination was performed. The aspirate was dry. The core biopsy showed a hypercellular marrow with a heavy infiltrate of Mycobacterium avium intracellulare infection (ZN stain in figure). She was started on 4-drug antituberculosis treatment, and 2 weeks later her platelet count was 30 109/L. The platelet count steadily rose to 150 109/L by day 20 and was maintained thereafter.