Pneumonia During Sirolimus Therapy for Kaposiform Hemangioendothelioma.

Sirolimus is an effective therapy for children with kaposiform hemangioendothelioma with or without the Kasabach-Merritt phenomenon. We report the case of a child with kaposiform hemangioendothelioma and the Kasabach-Merritt phenomenon who developed pneumonia (PCP) while on sirolimus and a prednisolone taper, after lack of adequate response to prednisolone, propranolol, and vincristine. He had a prompt positive clinical and laboratory response to sirolimus, but 4 weeks after starting it, at the age of 4 months, he developed PCP.