Kaposiform Hemangioendothelioma of the Mediastinum With Kasabach-Merritt Phenomenon Presenting With Pericardial Effusion in a 2-Month-Old

Kaposiform hemangioendothelioma (KHE) is a rare vascular and lymphatic tumor of childhood that commonly presents on the skin and extremities. KHE of the mediastinum affecting the heart and great vessels is extremely rare and often locally aggressive. We describe our case of mediastinal KHE with Kasabach–Merritt phenomenon presenting in a 2-month-old with persistent pericardial effusion and thrombocytopenia in the absence of cutaneous findings. Treatment success was achieved with sirolimus, propranolol, and an initial prednisolone wean.