Pneumocystis carinii pneumonia radiographically simulating tuberculosis.

Eight immunocompromised patients presented with upper lobe infiltrates that radiographically simulated tuberculosis. Bilateral lobar consolidation was present in 5, and apical or posterior segmental consolidation was present in 3. Pneumocystis carinii was diagnosed in 7 patients from material obtained at bronchoscopy after sputum stained for mycobacteria had been negative. In the eighth patient, sputum submitted for cytologic evaluation demonstrated P. carinii. The 7 patients surviving this episode of pneumonia responded clinically and radiographically to specific therapy directed against P. carinii. Predominant upper lobe involvement has not been previously emphasized as a pattern of P. carinii pneumonia but should be considered in immunocompromised patients.