Corticosteroid-to-sirolimus sequential therapy: a case series of infantile kaposiform hemangioendothelioma associated with Kasabach-Merritt phenomenon.

Background: Kaposiform hemangioendothelioma (KHE) with Kasabach-Merritt phenomenon (KMP) is a rare and life-threatening vascular tumor in infants, characterized by severe thrombocytopenia and consumptive coagulopathy. Although corticosteroids and sirolimus have both been used in treatment, there is no consensus on the optimal regimen, and evidence remains limited regarding sequential therapeutic strategies. This study aimed to explore the efficacy and safety of corticosteroid-to-sirolimus sequential therapy in a retrospective case series. Methods: From June 2022 to December 2024, nine infants diagnosed with KHE and KMP at our hospital received corticosteroid-to-sirolimus sequential therapy. Initial treatment included intravenous methylprednisolone (4 mg/kg/day), followed by a switch to oral methylprednisolone (4 mg/kg every other day) in combination with oral sirolimus (0.8 mg/m Results: All patients achieved a platelet count ≥100×10 Conclusions: Corticosteroid-to-sirolimus sequential therapy demonstrated favorable short-term efficacy and acceptable safety in this small series of infants with KHE and KMP. However, given the limited sample size and lack of long-term follow-up beyond two years, further prospective studies are necessary to validate these findings and assess potential late relapses or adverse effects.