Pneumocystis Pneumonia and Acute Kidney Injury Induced by Everolimus Treatment in a Patient with Metastatic Breast Cancer

Everolimus, an inhibitor of the rapamycin pathway, is administered with the combination of an aromatase inhibitor for the treatment of metastatic estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancers. Interstitial lung disease is a well-known major adverse event associated with everolimus treatment, but it is often difficult to distinguish between interstitial lung disease and Pneumocystis pneumonia, a lung infection. Acute kidney injury is another adverse event that is associated with everolimus use. In this article, we report a case of Pneumocystis pneumonia without respiratory symptoms and acute kidney injury induced by everolimus treatment in a patient with ER-positive and HER2-negative metastatic breast cancer.