Giant cell tumor of the ischium: unusual site and outcome.

We have described an unusual case of giant cell tumor of the ischium. The remarkable features of the case are that it occurred in a relatively rare site and that it transformed radiologically from a localized, well circumscribed lesion into a very destructive lesion over a period of several months, though histologically it remained benign in appearance. The lesion was successfully treated by a modified hemipelvectomy. We emphasize that the treatment of choice in giant cell tumor of bone is total en bloc excision and not curettage or irradiation.