Pneumocystis carinii Pneumonia Masquerading as Tuberculosis

Abstract

Recent laboratory studies indicate that genetic diversity exists in human strains of Pneumocystis carinii. Structural and functional variability in infecting strains could result in differences in host-parasite interactions and the natural history of P carinii pneumonia. We report 5 unusual cases in which the clinical presentation mimicked tuberculosis. All patients were cared for at a university-based public hospital clinic in Los Angeles, Calif, during a 2-year period. These patients were chronically ill, had lost weight, and each had cavities or cystic spaces as the primary radiographic findings. None were receiving aerosol pentamidine and only one had a history of smoking. Four patients were initially treated for tuberculosis and the fifth for disseminated Mycobacterium avium complex. Pneumocystis carinii was the only pathogen identified in each case. The unusual clinical presentations delayed the diagnosis of P carinii in all 5 cases. Practitioners must be aware of the variable presentations of P carinii pneumonia.

Granulomatous Pneumocystis carinii pneumonia in patients with malignancy

“…Since MSG binds to fibronectin receptors of type I epithelial cells, macrophage mannose receptors and alveolar surfactant proteins, it has been postulated that these changes in these highly immunogenic substances might alter the histological response of the host to P carinii. 2 A granulomatous response may be more likely with some strains of PCP than with others, and this may be responsible for some cases of granulomatous PCP.…”