Radiation-induced Supratentorial Osteosarcoma Following Curative Treatment of Infratentorial Ependymoma in a Child.

The development of secondary neoplasms following therapeutic cranial irradiation is rare and quite often lethal. Meningiomas, sarcomas, and high-grade gliomas are the most common tumors that manifest as a result of radiation therapy. We report the case of an 11-year-old child who presented with symptoms of supratentorial space-occupying lesion 7 years after curative surgery and cranial irradiation for a posterior fossa ependymoma. Magnetic resonance imaging of the brain revealed a right-sided temporoparietal dural-based contrast-enhancing lesion with evidence of overlying bone and skin involvement. The histological report of ependymoma from the previous surgery led us to suspect that we were dealing with a recurrence until the histopathology of the second surgery revealed highly malignant osteosarcoma. The child recovered fully and underwent chemotherapy, but ultimately succumbed to the disease. We report this case to highlight the importance of recognizing these neoplasms and to review its management.