Pneumocystis jiroveci pneumonia in an AIDS patient: Unusual manifestation of multiple nodules with multiloculated cavities

We report here a case of Pneumocystis jiroveci pneumonia (PCP) in an acquired immune deficiency syndrome (AIDS) patient with multiloculated cavitary lesions. Time-course analysis of chest computed tomography (CT) showed spontaneous ballooning of cavities and their disappearance after completion of PCP treatment. The characteristic radiological findings as well as histological features of a cavitary lesion suggested that check-valve phenomenon in small airways might explain the pathogenesis of cavities in this case.