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pulmonary histoplasmosis

Wednesday 19 October 2005

Definition: Pulonary fungal infections due to Histoplasma capsulatum.

Most examples of pulmonary histoplasmosis, including histoplasmoma and chronic histoplasmosis, are characterized by typical necrotizing granulomatous inflammation.

Only disseminated histoplasmosis is recognized as causing a different reaction which consists of ingestion of organisms by macrophages without granuloma formation.


- bronchocentric granulomatosis
- fibrosing granuloma
- necrotizing granuloma

Clinical forms

- primary pulmonary histoplasmosis
- acute pulmonary histoplasmosis (20351490)
- progressive disseminated histoplasmosis
- chronic cavitary histoplasmosis

Acute pulmonary histoplasmosis

The histologic features of acute pulmonary histoplasmosis are not well described as this form of the disease is rarely biopsied. Acute pulmonary histoplasmosis may cause a lymphohistiocytic infiltrate with necrosis and vasculitis that is suggestive of LYG. This observation emphasizes the importance of examining special stains for organisms before diagnosing grade 1 LYG. (20351490)

Differential diagnosis

- Pneumocystic carinii infection
- Blastomyces dermatidis
- Torulopsis glabrata
- Penicillium marneffei

Case studies

- Case #601


- Biopsy findings in acute pulmonary histoplasmosis: unusual histologic features in 4 cases mimicking lymphomatoid granulomatosis. Mukhopadhyay S, Katzenstein AL. Am J Surg Pathol. 2010 Apr;34(4):541-6. PMID: 20351490