We report a case of giant cell tumor of the manubrium with radiological evi
dence of aggressiveness. Few cases of giant cell tumor of the sternum have
been published. Extensive surgery offers the best hopes of recovery. Cytoge
netic studies evidenced several clonal abnormalities including a 17q isochr
omosome. The TP53 suppressor gene is located at 17q13.1. Whether loss of on
e of the TP53 alleles may have contributed to the aggressive behavior of ou
r patient's tumor is discussed.