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[Pulmonary alveolar proteinosis: ultrastructural study of 4 cases]
L Garrido1, T Gledhill, M Martin
1Departamento de Patología, Hospital José Ignacio Baldó, Caracas, Venezuela.
Abstract:
Pulmonary Alveolar Proteinosis (PAP) is a rare and diffuse lung disease characterized by the abnormal deposition of PAS positive, lipoproteinaceous material in the alveolar spaces. It has been related, mainly, to alterations in the immune state and to secondary infections. We studied four cases of PAP diagnosed by light microscopy. In two cases we were able to demonstrate disseminated Histoplasmosis related to immunodeficiency states (AIDS and malnutrition), one case with Pneumocystis carinii infection and AIDS, and one case with no related pathology. Granular and electron dense material, concentric myelin figures, and variable-sized osmiophilic bodies were observed by electron microscopy. We found yeast-like structures, trophozoites and cysts in the alveolar spaces, in the Histoplasmosis and Pneumocystic carinii infection cases, respectively. In one of our cases, the circulating neutrophils showed crystalloid inclusions in the nucleus. PAP should be considered in the differential diagnoses of patients with pulmonary infiltrates.
Insights
Pulmonary Alveolar Proteinosis (PAP) is a rare lung disease. This study found PAP linked to infections like Histoplasmosis and Pneumocystis carinii in immunocompromised patients, suggesting its importance in diagnosing lung infiltrates.
Area of Science:
- Pulmonology
- Infectious Diseases
- Pathology
Background:
- Pulmonary Alveolar Proteinosis (PAP) is a rare diffuse lung disease.
- Characterized by abnormal lipoproteinaceous material deposition in alveoli.
- Often linked to immune alterations and secondary infections.
Observation:
- Four PAP cases were analyzed using light and electron microscopy.
- Two cases showed disseminated Histoplasmosis (AIDS, malnutrition).
- One case had Pneumocystis carinii infection and AIDS.
- One case had no associated pathology.
Findings:
- Electron microscopy revealed granular, electron-dense material, myelin figures, and osmiophilic bodies.
- Yeast-like structures (Histoplasmosis) and trophozoites/cysts (Pneumocystis carinii) were observed in alveoli.
- Crystalloid inclusions in neutrophils were noted in one case.
Implications:
- PAP should be considered in the differential diagnosis of pulmonary infiltrates.
- Highlights the association between PAP and underlying immunodeficiency states.
- Underscores the role of infectious agents in PAP pathogenesis.
