Pneumocystis pneumonia (PCP) is an atypical pulmonary infection and the most common opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). https://radiopaedia.org/articles/pneumocystis-pneumonia
Pneumocystis pneumonia: Presentation:HIV+ male with cough and shortness or breath. There is hazy, predominantly perihilar mid and upper zone opacification with some interstitial prominence. A few discrete cysts (pneumatocoeles) measuring up to 1cm can be seen. No pleural effusion. No obvious nodal enlargement.
:Pneumocystis carinii pneumonia. Chest X-ray (R) shows a thin-walled cyst in the right upper lobe (arrow). The left image shows multiple cysts in the apical regions related to pentamidine inhalation in a human immunodeficiency virus patient
Figure 2. Chest radiograph of an HIV positive person with a CD4 cell count below 200 cells/mm3, demonstrating the characteristic bilateral granular opacities of PCP. Bronchoscopy with bronchoalveolar lavage fluid microscopic examination revealed Pneumocystis cysts and trophic forms. Courtesy of Laurence Huang, MD.