Intra-alveolar fibrosis

Snyder, L.S., Hertz, M.I., Peterson, M.S. et al. (1991). Acute lung injury pathogenesis of intra-alveolar fibrosis. J. Clin. Invest. 88, 663-673. 

Peyrol S, Cordier JF, Grimaud JA. Intra-alveolar fibrosis of idiopathic bronchiolitis obliterans-organizing pneumonia. Cell-matrix patterns. Am J Pathol 1990 137 155-170. 

V. Mechanisms of Intra-Alveolar Organization and Fibrosis, and its Resolution... 

Pneumocystis pneumonia occurs in patients with congenital or acquired immunodeficiency, for instance transplant patients and others who are receiving immunosuppressive therapy. Not infrequently, Pneumocystis pneumonia coexists with other pulmonary infections. The infection may be diffuse or focal, with a propensity to affect the lower lobes. In contrast with several other forms of pneumonia, there is no fibrinous pleurisy. The alveolar septa are increased in thickness and infiltrated with plasma cells and lymphocytes. The characteristic feature is the intra-alveolar exudate. This is foamy and strongly periodic acid-Schiff (PAS) positive, being composed of parasitic cysts. An intra-alveolar eellular reaction to the exudate is absent, and a few areas of hyaline membrane formation may be found. The diagnosis may be obtained by lung biopsy material. The organism may also be seen in sputum. In some instances, diffuse interstitial fibrosis may be the end result. 

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