A febrile young infant with splenomegaly and ecchymoses.

We discuss a young infant who presented to the emergency department with fever, ecchymoses, and splenomegaly with subsequent diagnosis of infant acute lymphoblastic leukemia. We review the infant's presentation, diagnostic, and therapeutic interventions, as well as the rare diagnosis of infant acute lymphoblastic leukemia and its poor prognosis. We pay particular attention to the hyperleukocytosis seen in this patient, a true oncologic emergency, and its treatment in the emergency department setting.