Although an osteosarcoma appears to be a solitary lesion clinically, as in this instance, only routine radiographic skeletal survey in such cases will detect multiple osseous involvement. Ross (1964) reported that in ninety-eight cases of osteosarcoma arising in apparently normal bone, fifteen showed metastases to other bones, a much higher incidence than previously recorded. It is also possible that multicentric osteosarcomata, although undoubtedly rare, may be discovered more often if a radiological survey is done. In many large series of osteosarcomata no mention of a skeletal survey has been made, and, while this is routine in some centres, it is not yet general practice.