Pneumocystis jirovecii pneumonia following everolimus treatment of metastatic breast cancer.

Everolimus is an inhibitor of mammalian target of rapamycin with anti-tumour activity. While everolimus is known to cause drug-induced pneumonitis, it is rarely associated with Pneumocystis jirovecii pneumonia (PJP). We report a patient on everolimus therapy for metastatic breast cancer that developed PJP. Diagnosis was based on clinical features and a quantitative polymerase chain reaction for P. jirovecii DNA. Clinicians should consider PJP as a potential cause of pulmonary infiltrates in patients treated with everolimus