# Fungal infection detected from a peripheral blood smear review

**Authors:** Mireia Pallarés, Jorge Medina, Marc Garreta, Emma Padilla, Teresa Villalba, Josefa Pérez, Antonio Casabella

PMC · DOI: 10.1515/almed-2025-0131 · Advances in Laboratory Medicine · 2025-10-02

## TL;DR

A blood smear review helped detect a rare fungal infection, showing the importance of lab collaboration and detailed analysis.

## Contribution

The case demonstrates how blood film morphology can aid in diagnosing histoplasmosis.

## Key findings

- Blood film review revealed yeast-like inclusions in neutrophils, suggesting H. capsulatum infection.
- Positive results for fungal biomarkers and HIV serology confirmed the diagnosis.
- The case emphasizes the value of morphological analysis and interdepartmental communication in diagnosis.

## Abstract

Histoplasmosis is a lung and blood disease caused by a dimorphic fungus, Histoplasma capsulatum, which causes non-specific clinical manifestations making differential diagnosis aimed at its detection difficult.

We explore the case of a 28-year-old man whose blood test revealed pancytopenia, which led to review of the blood film, which showed yeast-like cytoplasmic inclusions in some of the neutrophils, suggestive of H. capsulatum infection. Given the suspicion, the laboratory expanded tests for the detection of fungal biomarkers such as galactomannan antigen and B-D-glucan, in addition to HIV serology, which were positive.

This case highlights the importance of the morphological review of the blood film in the laboratory, as it provides very valuable and relevant information for the diagnosis of many diseases. As well as the importance of communication between the different departments in the laboratory.

## Linked entities

- **Diseases:** histoplasmosis (MONDO:0018312)
- **Species:** Histoplasma capsulatum (taxon 5037)

## Full-text entities

- **Diseases:** pancytopenia (MESH:D010198), H. capsulatum infection (MESH:D006660), lung and blood disease (MESH:D008171), Fungal infection (MESH:D009181)
- **Chemicals:** B-D-glucan (-)
- **Species:** Saccharomyces cerevisiae (baker's yeast, species) [taxon 4932], Histoplasma capsulatum (species) [taxon 5037], Human immunodeficiency virus 1 (no rank) [taxon 11676]

## Full text

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## Figures

2 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12994701/full.md

## References

10 references — full list in the complete paper: https://tomesphere.com/paper/PMC12994701/full.md

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Source: https://tomesphere.com/paper/PMC12994701