Postradiation Osteoblastic Osteosarcoma in the Iliac Region: Report of a Case with Multiple Cancers

Abstract

Although rare, osteosarcoma is the most frequent post-radiation second malignancy of the bone. We present a case of an osteoblastic osteosarcoma that occurred in a woman with a history of two neoplasms, as an example of multiple treatment-associated neoplasms. In fact, prior to the development of this osteosarcoma, our patient had been diagnosed with a breast carcinoma 24 years earlier, which had been treated by quadrantectomy, followed by radiotherapy, but it had recurred after 7 years. Thus, the patient had undergone mastectomy, followed by 4 years of tamoxifen. Then, 14 years later, she developed the second tumor, an endometrial adenocarcinoma, which was treated by surgery and adjuvant radiotherapy. Afterwards, a neoplasm developed in the pelvic bones, which histologically proved to be an osteosarcoma. Athough considered low, there is some risk of developing an endometrial cancer after tamoxifen protracted therapy. Since germline mutation analyses for p53 and RB1 resulted negative in our case, Thus, the treatment could have played a prominent role in our patient.