A vascular mass localized in the face and the neck was displayed by ultrasonography in a 38-week-old male fetus. At birth, the mass was bulky and purplish. The newborn breathed spontaneously but with severe desaturation. During laryngoscopy, we observed an obstruction of the larynx with a left-shift caused by the hemorrhagic mass. Blood analysis revealed anemia, severe thrombocytopenia, and coagulation disorders. The diagnosis of kaposiform hemangioendothelioma (KHE) complicated by a Kasabach–Merritt phenomenon (KMP) was put forward and treatment with propranolol, corticoids, and vincristine was initiated. Platelets were transfused daily for 8 days but did not resolve the thrombocytopenia. At day 8, we added sirolimus to the treatment and noted a rapid response with the normalization of the platelet count within 1 week and a significant regression of the mass. In this paper, we review the clinical and biological features of hemangioendothelioma associated with KMP and discuss its current and future treatment. Sirolimus seems to be very promising.