[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Central nervous system](https://durgical.com/en/general-pathology/areas/cns/) › Fungal infections of the CNS

# Fungal infections of the CNS

- Lesion

Fungi reach the brain mostly in people with weak immunity, causing chronic meningitis, abscesses or blocked and bleeding vessels.

Updated Nov 12, 2026

## Key points

- Cryptococcus neoformans: meningitis in AIDS, with little inflammation; capsule seen with mucicarmine or India ink, and cryptococcal antigen in CSF and blood.
- Gelatinous ‘soap bubble’ cysts of Cryptococcus in the basal ganglia within enlarged perivascular spaces.
- Mucormycosis: rhino-orbito-cerebral spread in diabetic ketoacidosis; broad ribbon-like hyphae without septa invade arteries.
- Aspergillus: narrow septate hyphae branching at acute angles; angioinvasion and hemorrhagic infarcts in neutropenia.
- Candida: multiple microabscesses in critically ill and neutropenic patients.
- Cryptococcus gattii can infect immunocompetent people and form mass lesions (cryptococcomas).

## What it is

Fungal infection of the CNS usually follows spread through the blood in immunocompromised patients, or direct extension from the sinuses in poorly controlled diabetes. Three patterns occur, often together: chronic meningitis, vasculitis with infarcts, and parenchymal abscesses or granulomas. Cryptococcus is the classic cause of meningitis in AIDS; Mucor and Aspergillus invade vessel walls and cause hemorrhagic infarcts. Endemic fungi such as Histoplasma and Coccidioides involve the brain after lung infection.

## Structure

- Cryptococcal meningitis: gelatinous exudate, organisms in the subarachnoid space and perivascular spaces with sparse inflammation in advanced AIDS.
- Angioinvasive fungi: thrombosed arteries packed with hyphae and hemorrhagic necrosis of the territory supplied.

## Fungi that infect the CNS

| Fungus | Host | Pattern | Morphology |
| --- | --- | --- | --- |
| [Cryptococcus](https://durgical.com/en/conditions/cryptococcal-meningitis/) | AIDS, transplant; C. gattii in healthy hosts | Chronic meningitis, perivascular cysts | Budding yeast with a thick capsule |
| Candida | ICU, neutropenia | Microabscesses, granulomas | Yeasts and pseudohyphae |
| Mucorales | Diabetic ketoacidosis, iron overload, neutropenia | Spread from sinus and orbit, vascular invasion | Broad hyphae without septa, right-angle branches |
| [Aspergillus](https://durgical.com/en/conditions/aspergillosis/) | Neutropenia, transplant | Septic infarcts, hemorrhage | Narrow septate hyphae, acute-angle branches |
| [Histoplasma, Coccidioides, Blastomyces](https://durgical.com/en/conditions/histoplasmosis/) | Endemic areas, often with immunosuppression | Meningitis, granulomas | Small intracellular yeasts, spherules or broad-based buds |

## Markers

- Mucicarmine (cryptococcal capsule)
- Grocott methenamine silver
- PAS
- Cryptococcal antigen

## Clinical notes

- Cryptococcal meningitis gives headache and confusion with very high opening pressure; repeated CSF drainage is part of care.
- Histoplasmosis and paracoccidioidomycosis are endemic in parts of Colombia and Latin America.

## Memory aid

Crypto bubbles in quiet spaces; Mucor and Aspergillus drill through the vessel walls.

## Test yourself

Think of the answer, then tap the question to see it.

## Which stain highlights the capsule of Cryptococcus in tissue?

Mucicarmine, which stains the polysaccharide capsule red.

## How do Mucor hyphae differ from Aspergillus hyphae?

Mucor hyphae are broad, ribbon-like, without septa and branch at right angles; Aspergillus hyphae are narrow, septate and branch at acute angles.

## In which metabolic state does rhino-orbito-cerebral mucormycosis classically occur?

Diabetic ketoacidosis.

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## Elsewhere in DurgiPedia

- [Secondary immunodeficiency: HIV, malnutrition, drugs, asplenia](https://durgical.com/en/immunology/secondary-immunodeficiency-hiv-malnutrition-drugs-asplenia/)

## Connections

## Related 5

- [Acute meningitis: pyogenic vs aseptic](https://durgical.com/en/general-pathology/acute-meningitis-pyogenic-vs-aseptic/)
- [HIV in the brain and PML](https://durgical.com/en/general-pathology/hiv-in-the-brain-and-pml/)
- [Parasitic brain infections](https://durgical.com/en/general-pathology/parasitic-brain-infections/)
- [Granulomatous inflammation: caseating vs non-caseating, the causes to know](https://durgical.com/en/general-pathology/granulomatous-inflammation-caseating-vs-non-caseating-the-causes-to-know/)
- [Granulomatous pneumonia: tuberculosis and endemic fungi](https://durgical.com/en/general-pathology/granulomatous-pneumonia-tuberculosis-and-endemic-fungi/)

## Related conditions 6

- [Cryptococcal meningitis](https://durgical.com/en/conditions/cryptococcal-meningitis/)
- [Aspergillosis](https://durgical.com/en/conditions/aspergillosis/)
- [Histoplasmosis](https://durgical.com/en/conditions/histoplasmosis/)
- [HIV infection and AIDS](https://durgical.com/en/conditions/hiv-infection-and-aids/)
- [Type 1 diabetes mellitus](https://durgical.com/en/conditions/type-1-diabetes-mellitus/)
- [Diabetic ketoacidosis](https://durgical.com/en/conditions/diabetic-ketoacidosis/)

## Microorganisms 6

- [Cryptococcus neoformans](https://durgical.com/en/microbiology/cryptococcus-neoformans/)
- [Candida albicans](https://durgical.com/en/microbiology/candida-albicans/)
- [Mucorales (Rhizopus, Mucor)](https://durgical.com/en/microbiology/mucorales/)
- [Aspergillus fumigatus](https://durgical.com/en/microbiology/aspergillus-fumigatus/)
- [Histoplasma capsulatum](https://durgical.com/en/microbiology/histoplasma-capsulatum/)
- [Coccidioides immitis](https://durgical.com/en/microbiology/coccidioides-immitis/)

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [About Cryptococcosis | Cryptococcosis | CDC](https://www.cdc.gov/cryptococcosis/about/index.html) (Centers for Disease Control and Prevention, 2026).

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Representative model, for educational purposes only.

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