Primary Ewing Sarcoma of the Mastoid: A Novel Case Mimicking Acute Mastoiditis.

Ewing sarcoma (EWS) is a primitive neuroectodermal tumor arising in bone or soft tissue. It is the second most common primary bone malignancy of children and adolescents, with a peak incidence in the second decade of life. It most often arises in the long bones of the extremities and pelvis. Here, we present a novel case of EWS arising from the mastoid bone in a 5-year-old African American male who presented with symptoms of acute mastoiditis. This unique presentation highlights the importance of considering EWS in a patient who presents with atypical mastoiditis or a rapidly growing mass in the postauricular region.