CD4 and AIDS: Tenpercent to 30% of HIV-negative patients with CM have no apparent underlying cause.4 Diagnosis is usually through cryptococcal antigen test and culture of CSF.Risk factors include AIDS, organ transplants, chronic corticosteroid use, cancer,and idiopathic CD4+ lymphocytopenia.3 Although neuroimaging is usually normal in CM, cryptococcomas, pseudocysts,and obstructing hydrocephalus can be seen.5 MRI is considered the most sensitive imaging modality, but can also beindistinguishable from other differentials including tuberculosis or metastatic malignancy.6