Atypically presenting kaposiform hemangioendothelioma of the knee: ultrasound findings

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor of early childhood and infancy. Kasabach–Merritt phenomenon, a common complication of KHE, is characterized by life-threatening thrombocytopenia, hemolytic anemia, and consumption coagulopathy. There may be atypical cases that do not present with Kasabach–Merritt phenomenon and do have atypical imaging findings. Knowledge of atypical imaging features may assist radiologists in identifying KHE. In this report, we present a 4-year-old case of KHE with atypical ultrasound findings.