Imaging findings of radiation-induced sarcoma of the head and neck.

We set out to retrospectively review the clinical and imaging features of patients with post-radiation sarcoma, especially in the head and neck region. We reviewed the records of 4194 patients with carcinoma of the head and neck region who had a history of radiation. They had undergone CT and/or MRI. Medical records were reviewed for the primary diagnosis, radiation history and latency period to the development of sarcoma. The patients included four men and two women with a mean age of 64.5 years. The mean latency period for the development of sarcoma was 11.5 years. Primary diagnoses were maxillary carcinoma, nasopharyngeal carcinoma, adenoid cystic carcinoma of the oral floor, tonsilar carcinoma, soft palate carcinoma and tongue carcinoma. Histopathological examinations revealed osteosarcoma, spindle cell sarcoma, chondrosarcoma, malignant peripheral nerve sheath tumour, spindle cell carcinoma and malignant fibrous histiocytoma, respectively. Common findings were a heterogeneous and well-enhanced soft tissue mass and bone destruction. There is at present little or no prospect for the effective prevention of radiation-induced sarcoma of the head and neck. This emphasizes the importance of the earliest possible diagnosis for such patients. The imaging findings are not diagnosis specific, but strict follow-up within the radiation field by CT and MRI and an appreciation of the expected latency period may help to provide the diagnosis. When radiotherapy is performed for head and neck neoplasms, periodic follow-up observations may be necessary for many years.