Sirolimus-associated pericardial effusion with cardiac tamponade and interstitial pneumonitis in a hematopoietic stem cell transplant recipient.

Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, is a potent immunosuppressant that is increasingly used in prevention and treatment of graft-vs-host disease (GVHD) in allogeneic hematopoietic stem cell transplant (HSCT) patients. However, data regarding its adverse effects in HSCT patients remain limited. We describe an 18-year-old HSCT patient with a history of invasive fungal infection, who developed pericardial effusion with cardiac tamponade and interstitial pneumonitis while receiving sirolimus for GVHD prophylaxis. Our case illustrates potentially life-threatening complications of sirolimus use in allogeneic HSCT patients.