40-year-old male with history of HIV-infection (undetectable viral load, CD4 107) compliant on treatment with Highly-Active-Anti-Retroviral-Treatment for 2 years, disseminated Mycobacterium-Avium-Intercellular-Complex(MAC) treatment (1 month prior to presentation), polysubstance abuse presented with apathy and mild left hemiparesis sub-acutely.
MRI brain showed extensive confluent T2-hyperintense signal in the right cerebral hemisphere crossing the anterior corpus callosum, left frontal-temporal lobes, deep gray nuclei with extension into pons, cerebellar hemispheres and middle cerebellar peduncles as well as the optic-chiasm with atrophy of intra-orbital optic nerves. Patchy nodular post contrast enhancement “in a starry night pattern” throughout the regions of abnormal T2-signal was seen without leptomeningeal/pachymeningeal enhancement. There were enhancing cervical cord lesions at multiple levels. The differential diagnosis was wide including Neoplasm, Immune/Inflammatory mediated, Infectious and Demyelination.
Serum studies including autoimmune and infectious work up was negative. CSF showed glucose of 58 mg/dl and protein of 100mg/dl. RPR , CSF-toxoplasma-PCR, CSF-JC-virus-DNA and EBV-DNA by PCR were negative. CSF flow-cytometry performed twice, did not show lymphocytes. CSF-fungal-cultures were negative. QuantiFERON-TB-Gold test was indeterminate.
CT of the thorax-abdomen-pelvis showed extensive lymphadenopathy. Lymph node biopsy showed reactive lymphadenopathy but no evidence of neoplasm or infection, unfortunately necessitating Brain biopsy which confirmed necrotizing granulomatous inflammation with acid-fast bacilli positive with CD68 highlighting the histiocytes. He was presumed to be Mycobacterium-Tuberculosis and started on 4-drug regimen. Cultures (after 6 weeks) from brain biopsy showed Mycobacterium-Avium-Intercellulare confirming the diagnosis of disseminated CNS MAC.