The Kasabach-Merritt phenomenon (KMP) is a rare clinical condition characterized by consumptive coagulopathy, thrombocytopenia, and hypofibrinogenemia. KMP frequently accompanies vascular tumors such as kaposiform hemangioendothelioma (KHE) and tufted angioma.A term female infant with diffuse petechiae, thrombocytopenia and a small lumbar mass was referred to our hospital on the 5th day with the diagnosis of KMP. Physical examination revealed generalized petechiae, hematoma on the right inguinal region, and a large ecchymosis in the lumbar region. She was diagnosed with disseminated intravascular coagulation (DIC) and supportive treatment was provided. Magnetic resonance imaging revealed a 86x54x76 mm retroperitoneal mass consistent with cavernous hemangioma pushing the aorta and right kidney anteriorly, invading the vertebra and extending to the spinal canal. Biopsy could not be obtained due to severe DIC. KHE was considered with the clinical findings of a giant vascular mass, KMP, and severe DIC. The patient was managed with pulse steroid, vincristine and actinomycin-D treatments. She was discharged at 2 months as the mass became smaller and KMP improved.If KMP and DIC develop in vascular tumors, the risk of bleeding may increase mortality and morbidity. In this malignant clinical condition, KHE should be considered and therapy should be planned accordingly. DIC and thrombocytopenia should be managed by supportive therapies

Keywords: Kasabach-Merritt phenomenon, Kaposiform hemangioendothelioma, Newborn