Fatal high-grade skull osteosarcoma 30 years following radiotherapy for Cushing's disease.

Cushing's disease is treated with transsphenoidal resection as first-line therapy, with radiotherapy used in cases of incomplete resection, disease recurrence or persistent hypercortisolism. The most common long-term adverse outcome of pituitary tumour irradiation is hypopituitarism occurring in 30-60% of patients at 10 years, and less commonly, vision loss and oculomotor nerve palsies, radiation-induced brain tumours and sarcomas. Currently proposed characteristics of radiation-induced osteosarcomas include: the finding of a different histological type to the primary tumour, has developed within or adjacent to the path of the radiation beam, and a latency period of at least 3 years. Treatment of osteosarcoma of the skull include complete surgical excision, followed by systemic chemotherapy and/or radiotherapy. Overall prognosis in radiation-induced sarcoma of bone is poor. Newer techniques such as stereotactic radiosurgery may reduce the incidence of radiation-induced malignancies.