Thorotrast-induced extraskeletal osteosarcoma of the cervical region. Report of a case.

This is the seventh reported case of soft tissue sarcoma attributed to thorotrast extravasated during the course of an injection for arteriography. An extraskeletal osteosarcoma occurring the cervical region of a 51-year-old man 30 years after a cerebral arteriogram is presented. The other reported cases include a fibrosarcoma, two neurofibrosarcomas, two spindle cell sarcomas, and an extraskeletal chondrosarcoma. The latency period has varied from 5 to 30 years. The thorotrast granules are readily identified in macrophages near or adjacent to the tumor, and the demonstration of alpha tracks on autoradiographs is diagnostic.