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Last Updated: October 1, 2018

Cryptococcus neoformans is a common organism found in the soil and the most common fungal infection of the central nervous system. It is encapsulated with a hydrophilic polysaccharide that takes up India Ink stain. It is the second most common opportunistic infection in HIV/AIDS patients (second to the parasite toxoplasmosis).

Patients with CD4+ count less than 100 cells/mL are at greatest risk for contracting cryptococcosis, particularly in endemic areas. Clinical presentation is nonspecific, including headache, neck stiffness, nausea, seizure, and possibly without localizing neurologic deficits.

Imaging Features

There are three predominant forms of pathology of cryptococcus infection in the brain: meningitis, parenchymal cryptococcoma, and gelatinous pseudocysts associated with the perivascular spaces in the basal ganglia. These pathologic findings may produce minimal changes on imaging and in many cases one must have an elevated level of suspicion in the appropriate clinical setting to diagnose this disease.

  • CT:
    • Usually normal.
    • Nonspecific findings include hydrocephalus, atrophy, edema, and...