MULTICENTRIC GIANT-CELL TUMOR OF BONE

Giant cell tumor of bone accounts for 4% to 5% of primary bone tumors in the United States. Multicentric giant cell tumors occur in <1% of a ll patients with giant cell tumors, and only 43 patients with multicen tric giant cell tumor have been reported on in the literature, This se ries presents 3 additional cases of multicentric giant cell tumor, inc ludes updated data for 2 patients previously reported on in the litera ture, and reviews 24 cases previously reported on in detail in the lit erature. The mechanism by which giant cell tumor involves multiple loc ations is not known. Multicentric giant cell tumor, in contrast to uni focal giant cell tumor, has a tendency to involve the hands, feet, and metaphysis/diaphysis of long bones and to occur in a slightly younger population. In 15 of the 29 patients reviewed, a second lesion did no t develop for >2 years after their initial presentation. Eighteen of t hose 29 patients had >2 sites of tumor involvement, 1 of whom had 11 l esions. Two of the 5 patients in the authors' series presented with a spectrum of disease activity, with latent, active, and aggressive lesi ons present throughout the observation period.