Development of Secondary Osteosarcoma After TBI and Allogeneic Bone Marrow Transplant: A Case Series of 3 Patients.

Osteosarcoma can rarely occur as a subsequent malignant neoplasm after cancer therapy. Children who underwent treatment for cancer and received an allogeneic hematopoietic cell transplant are at a higher risk to develop secondary malignancies. Radiation is also a known risk factor, but estimating the quantitative risk is difficult due to the rarity of the condition and long latency period between primary and secondary cancer. In this report, we present 3 patients diagnosed with leukemia as young children who received hematopoietic cell transplants with total body irradiation as part of the conditioning regimen, and later went on to develop secondary osteosarcoma.