Fibrosarcoma of the mandible following supravoltage irradiation. Report of a case.

Supravoltage irradiation is commonly thought not to be carcinogenic. Several recent studies question this concept, as does our case report. A 50-year-old woman with stage 1 squamous carcinoma of the left side of the tongue was treated in 1973 with 73 Gy of supravoltage irradiation. Twelve years later a painful, ulcerated lesion that eventually was shown to be fibrosarcoma developed in the contralateral mandible. The fibrosarcoma in this case fulfills all criteria for diagnosing radiation-induced neoplasia and demonstrates that supravoltage irradiation, like other forms of irradiation, can cause malignancy. The occasional occurrence of sarcoma should be recalled during follow-up of patients treated with supravoltage radiation. Similarly, the possibility of radiation-induced tumors should be considered in planning treatment for younger patients with tumors that can be treated equally well by surgery or irradiation.