Osteosarcoma of the pelvis. A clinical and histopathological study of twenty-five patients.

Twenty-five patients who had an osteosarcoma of the pelvis were treated at the University of Florida between 1967 and 1990. Two of these patients had underlying Paget disease, and five had received previous radiation therapy to the pelvis. Common problems in this series of patients included delays and errors in establishment of the diagnosis, underestimation of the extent of the tumor on the radiographic staging studies, histopathological findings of local extension next to and into pelvic structures, widespread invasion into major pelvic veins, and microscopic foci of tumor in otherwise normal tissue. These problems led to difficulty in gaining local control of the tumor with any type of operative procedure. Of the eighteen patients who had a resection, only four had a contamination-free wide margin, and a local recurrence developed in thirteen. Only one patient, who had no evidence of disease eleven years after treatment, was alive at the time of writing. Because of the tendency for venous invasion, the radiographic staging studies should include a thorough evaluation of the blood vessels adjacent to the tumor.