Unusual Presentation of Pneumocystis Pneumonia in an Immunocompetent Patient Diagnosed by Open Lung Biopsy

Pneumocystis pneumonia (PCP) is the most common opportunistic infection in acquired immune deficiency syndrome (AIDS) patients. It is a fungal infection with Pneumocystis jiroveci which can be isolated from bronchoalveolar lavage of healthy subjects. The infection occurs mainly in HIV patients; with CD4 lymphocyte count drop to less than 200 cells/μL. PCP has been reported in non-HIV patients with other risk factors such as immunosuppressive medications, malignancies, and other inflammatory conditions. PCP has been rarely reported in immunocompetent subjects. However, in most of these patients, PCP occurred after a period of acute illness with bacterial pneumonia and antibiotic therapy. In this report, we describe a case of PCP in an immunocompetent patient with nonreactive HIV and no immunosuppressive risk factors. The patient had large pulmonary nodules discovered incidentally on chest film as preoperative evaluation for hip surgery. Bronchoalveolar lavage, transbronchial biopsies (TBB), and computed tomography (CT) guided needle biopsy were all negative for P. jiroveci. PCP diagnosis was made after open lung biopsy and wedge resection. To our knowledge, this is the first case of PCP in immunocompetent patient with negative BAL, TBB and CT guided biopsy. The diagnosis of PCP required open lung biopsy and the patient recovered without complications.