Case report: A rare case of Ewing's sarcoma and osteosarcoma at different sites 10 years apart

Diagnosis of osteosarcoma in a patient previously treated for Ewing sarcoma

Primary malignant bone tumors, whether Ewing sarcoma or osteosarcoma, are a rare type of tumor. The sequential occurrence of two bone sarcomas, Ewing sarcoma and high-grade osteosarcoma, in the same patient at two different locations is an exceptionally rare phenomenon. We present the case of a 13-year-old girl who presented with a high-grade osteoblastic osteosarcoma of the distal femur, 7 years after treatment for Ewing sarcoma of the left pelvis. She did not receive radiation therapy. Following the recent developing multidisciplinary therapy, long-term follow-up for monitoring latent treatment-related adverse effects may be necessary for survivors of primary malignant bone tumors.

Sequential Ewing's sarcoma and osteosarcoma

The sequential occurrence of two primary bone tumors, Ewing's sarcoma and osteosarcoma in the same patient at two different anatomical sites 5 years apart is rare. We report a case of 12-year-old boy who after treatment for Ewing's sarcoma of proximal fibula subsequently presented, 4 years later, with a high-grade fibroblastic osteosarcoma of the proximal humerus. The patient was also found to have a rare gene tranlocation t (7;22) instead of the more common t (11;22).