Kaposiform hemangioendothelioma with Kasabach-Merritt syndrome mistaken for child abuse in a newborn.

Kaposiform hemangioendothelioma is a rare vascular neoplasm of childhood that may have an alarming and potentially misleading clinical presentation. Awareness of this entity is important to provide appropriate and immediate medical care. We report the case of a 24-day-old female newborn who presented with a large bruiselike lesion on the left leg. A diagnosis of cellulitis suspected to be secondary to child abuse was made and the patient subsequently was placed in foster care; however, the lesion did not resolve after treatment and relocation. On reevaluation at our institution, physical examination revealed a round, 3 x 4-cm, violaceous, indurated, fixed, nonblanching, nontender plaque with an ivory center and peripheral erythema over the anteromedial aspect of the left leg. Biopsy demonstrated a vascular neoplasm consistent with kaposiform hemangioendothelioma (KHE), and laboratory evaluation revealed thrombocytopenia, low fibrinogen levels, and elevated D-dimer levels, confirming a diagnosis of Kasabach-Merritt syndrome (KMS).