Epiphyseal primary location for osteosarcoma and Ewing sarcoma in patients with open physis.

Conventional osteosarcoma and Ewing sarcoma are the most common childhood malignant tumors of bone. These tumors arise in the metaphysis and diaphysis of long bones and may extend secondarily into the epiphysis. Primary epiphyseal location for these tumors is rare and may constitute a diagnostic and therapeutic challenge. The authors report two skeletally immature patients with an osteosarcoma and Ewing sarcoma limited to the epiphysis. Clinical, radiographic and histopathologic findings are discussed.