Metagenomic next-generation sequencing for pathology-suspected fungal infections at rare anatomical sites: a case series.

OBJECTIVE

Histopathology for suspected fungal infections lacks species-level identification and is prone to morphological mimics. The utility of metagenomic next-generation sequencing (mNGS) at rare anatomical sites is underexplored.

METHODS

We retrospectively analyzed 10 cases with histopathology suggestive of fungal infection at rare sites (brain, cardiac valve, bone, etc.). All underwent mNGS testing on formalin-fixed paraffin-embedded samples.

RESULTS

mNGS detected fungal DNA in 8/10 cases (80%), providing species-level identification (e.g., Cryptococcus, Candida, Fusarium, Rhizopus, Histoplasma). Polymicrobial infections were identified in 70%. mNGS corrected two misdiagnoses: one confirmed neurocysticercosis; another revealed only bacteria in a suspected fungal lesion. Antimicrobial resistance genes (ErmB) were identified in two cases.

CONCLUSION

mNGS enhances diagnostic precision at rare sites by enabling species identification, uncovering polymicrobial infections, and correcting morphological misdiagnoses, supporting targeted therapy.