Kaposiform Hemangioendothelioma

Sirolimus has demonstrated efficacy in the treatment of kaposiform hemangioendothelioma (KHE); however, a high rate of rebound growth following discontinuation has been reported, highlighting the clinical importance of establishing an appropriate withdrawal regimen.

To research and explore the antibody protection and immune memory after vaccination in children with KHE during sirolimus administration. To explore the feasibility (safety and efficacy) of vaccination in a timely manner during the administration of sirolimus in children with KHE. To search for back-up plans for vaccination regimens for KHE patients taking sirolimus in children who do not respond to primary vaccination.

The study will use blood (serum and plasma) and tissue obtained from participants undergoing prescribed surgical resection of vascular anomalies of interest proposed in this study. The study will also use blood (serum and plasma) and tissue collected and stored in a tissue bank maintained by the Department of Hematology/Oncology.