Ewing’s sarcoma /yo̅o̅″ingz/ [James Ewing, American pathologist, 1866–1943] , a malignant tumor that develops from bone marrow, usually in long bones or the pelvis. It occurs most frequently in adolescent boys and is characterized by pain, swelling, fever, and leukocytosis. The tumor, a soft, crumbly grayish mass that may invade surrounding soft tissues, may be difficult to distinguish histologically from a neuroblastoma or a lymphoma. Surgery, chemotherapy, and radiotherapy are often used in treatment. Also called endothelial myeloma, Ewing’s tumor. See also neuroblastoma, histiocytic malignant lymphoma.
