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Pathology of the human pulmonary paracoccidioidomycosis
Abstract:
Lungs of twelve patients with chronic paracoccidioidomycosis (Pb) were studied in an attempt to understand the pathogenesis of the pulmonary disease. Ribbons of the lung parenchyma including the hilar region and directed towards apical, basal and lateral regions were subdivided into sections from the hilar, intermediate and peripheral segments. The following histopathological reactions directly or indirectly related to P. brasiliensis were described and analysed in relation to the number of slides studied and the pulmonary region involved: pneumonic reaction; early granulomatous formation; mature and healed granulomata; mixed pattern (early and mature granuloma in the same pulmonary area visualized in the slide); pulmonary fibrosis. It was concluded that chronic pulmonary Pb is a recurrent disease affecting equally both lungs. Fibrosis was connected mainly with the progressive evolution of the granulomata towards cicatrization and to a lesser degree probably to a direct induction by the fungi. Based chiefly on the tendency of the fibrosis to run around bronchi and to make up septa interconnecting bronchi and vessels it was hipothesized that these findings were the result of a previous chronic specific lymphangitis by the fungi. Hilar fibrosis would be the result of this lymphangitis and/or of the progression of the specific granulomatous reaction seen in the hilar lymph nodes. Non specific forms of arteritis and areas of destructive emphysema related to granulomatous inflammation and fibrosis were described. Three cases developed pulmonary hypertension.
Insights
Chronic pulmonary paracoccidioidomycosis (Pb) is a recurrent lung disease affecting both lungs. Fibrosis, a key feature, results from granuloma healing and potentially direct fungal effects, leading to lymphangitis and emphysema.
Area of Science:
- Pulmonary Medicine
- Infectious Diseases
- Pathology
Background:
- Paracoccidioidomycosis (Pb) is a systemic fungal infection endemic in Latin America.
- Pulmonary involvement is common and can lead to chronic lung disease.
- Understanding the pathogenesis of chronic pulmonary Pb is crucial for effective management.
Purpose of the Study:
- To investigate the histopathological reactions in the lungs of patients with chronic paracoccidioidomycosis.
- To elucidate the pathogenesis of pulmonary fibrosis and associated lung changes in chronic Pb.
- To analyze the relationship between fungal presence, inflammatory responses, and tissue damage.
Main Methods:
- Histopathological analysis of lung tissue sections from twelve patients with chronic paracoccidioidomycosis.
- Detailed examination of lung parenchyma, including hilar, intermediate, and peripheral segments.
- Evaluation of various histopathological reactions: pneumonic, granulomatous (early, mature, mixed), fibrosis, arteritis, and emphysema.
Main Results:
- Chronic pulmonary Pb affects both lungs equally and is recurrent.
- Pulmonary fibrosis is primarily linked to granuloma cicatrization and possibly direct fungal induction.
- Findings suggest chronic lymphangitis and granulomatous reactions contribute to fibrosis, particularly in the hilar region.
- Non-specific arteritis, destructive emphysema, and pulmonary hypertension were observed in some cases.
Conclusions:
- Chronic pulmonary paracoccidioidomycosis is characterized by recurrent inflammation and fibrosis.
- Fibrosis development is closely associated with the healing process of granulomas and potential lymphangitis.
- The study highlights the complex interplay of inflammatory and fibrotic processes in the pathogenesis of chronic pulmonary Pb.