Vincristine-resistant Kasabach–Merritt phenomenon successfully treated with low-dose radiotherapy

In 1940, Kasabach and Merritt reported the case of an infant with a huge angioma causing thrombocytopeniarelated purple spots. This condition became known as the Kasabach–Merrit phenomenon (KMP), characterized by a huge hemangioma associated with thrombocytopenia and microangiopathic hemolytic anemia due to consumption coagulopathy [1]. The incidence of KMP in infants with a huge hemangioma is approximately 0.3%, but it is said that the mortality rate exceeds 30% among patients. A number of therapies have been reported for the treatment of KMP, but none have been uniformly effective. We report a case of life-threatening KMP, in which hemangioma of the right thigh (tufted angioma type) was successfully treated by low-dose radiotherapy after concurrent therapy with the agents prednisolone (PSL), interferon a-2a (IFN a-2a), and vincristine (VCR) failed to control it. 2 Case report