Metastasis from a giant-cell tumor of bone that is histologically benign
has become a recognized entity. To date, thirty-one pathologically proved
cases have been reported in the world literature. To this, we add eight
cases from our experience of more than 400 cases of histologically benign
giant-cell tumor of bone. The lungs are the principal site of metastasis,
the lesions being pathologically indistinguishable from the primary tumor.
The metastatic process is unpredictable as to clinical aggressiveness, and
the mortality rate is approximately 25 per cent. We advise aggressive
attempts at complete extirpation of metastases.