Fungal organisms in the brain (February 2017)
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* Sanjay Mukhopadhyay
* Andrea V. Arrossi
* Carol F. Farver

**TO THE EDITOR**: In their Clinical Picture article in the February 2017 issue, Barbaryan et al1 describe brain lesions in a young woman with human immunodeficiency virus infection who presented with seizures. Figure 3 illustrates Grocott-Gomori methenamine silver (GMS)-positive fungal organisms in a brain biopsy. The organisms appear helmet-shaped and crescent-shaped and contain an intracystic dot, morphologic features of *Pneumocystis jiroveci* cysts.2 We could not appreciate features of *Histoplasma* yeasts (smaller yeasts with diameter of 3 to 5 µm, oval to tapered shape, and narrow-based budding).

The distinction between the two organisms can occasionally be challenging because there is some degree of overlap in size and shape, and both are GMS-positive. It is interesting that in the current case, serologic studies for *Histoplasma* were positive. Multiple infections with opportunistic organisms are not uncommon in severely immunocompromised individuals, and it is possible that the patient may also have had concurrent histoplasmosis. Brain lesions caused by *Pneumocystis*, although rare, have been previously reported.3–5 Immunohistochemistry for *Pneumocystis* may be of interest in this very unusual case.

## Footnotes

*   [Editor’s note: Letters that comment on articles published in the *Journal* are sent to the author(s) for response. In this case, the authors felt that the letter did not require a reply.]

*   Copyright © 2017 The Cleveland Clinic Foundation. All Rights Reserved.

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