Congenital Ewing's sarcoma of the humerus

We report an extremely rare case of Ewing's sarcoma (ES) of the humerus in a Chinese neonate. Plain radiography and magnetic resonance imaging showed extensive neoplastic involvement of the humeral diaphysis and adjacent soft tissues, confirmed on histology and immunohistochemistry as being due to E S. This is the first report of congenital ES in a long bone. Since ultrasou nd at 20 weeks gestation showed a normal fetal skeleton, the ES may have be gun to develop in the late middle or third trimester.