pulmonary histoplasmosis

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.

Synopsis

 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

References

 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