Multicentric malignant transformation of multiple exostoses.

We treated a patient with large multiple chondrosarcomas derived from multiple cartilaginous exostoses. One sarcoma originated in the left pubic bone and the other sarcoma in the posterior aspect of the greater trochanter of the left femur. Thirty months after hindquarter amputation, the patient is alive without relapse. This is the first report of a patient with synchronous multiple malignant transformation of multiple cartilaginous exostoses.