Melanized Fungi in CNS Infections

Abstract

There are increasing reports of central nervous system infections due to melanized fungi worldwide. These brown pigment-containing fungi are often grouped under dematiaceous mycosis or phaeohyphomycosis. They are predominantly responsible for cerebral infections and brain abscesses, Cladophialophora bantiana, Exophiala dermatitidis, and Phialophora. Fungi under the Bipolaris genus are found in immunocompetent individuals who present with a chronic sinusitis which aggravates into secondary cerebral infection. The vehicle of transmission of phaeohyphomycosis is usually of exogenous nature, e.g., thorn/wood pricks. The melanin-like pigment found in their cell walls is responsible for immune evasion mechanisms. These golden-brown pigments can assist in making a presumptive diagnosis based on their microscopic visualization when examining histopathology samples. There are also cases of hematogenous spread leading to central nervous system involvement, due to penetrating head injuries and direct spread. Curvularia is a melanized mold found ubiquitously in soil, which although extremely rare, has the potential to cause life-threatening brainstem infection. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.