To evaluate the frequency of osteosarcoma involving the foot and determine the clinical
outcome of affected patients.
Material and Methods
We retrospectively reviewed the cases of osteosarcoma encountered between 1911 and
1992 at the Rizzoli Orthopedic Institute. In particular, we analyzed whether common
clinical, radiographic, or histologic features could lead to a correct diagnosis of
osteosarcoma of the foot.
The bones of the foot were the primary site of osteosarcomas in 12 cases—0.6% of the
entire series of such tumors at our institution during the study period. The mean
age of the patients was 33 years. Initial symptoms were usually pain and swelling.
Late diagnosis was common; the mean time interval between the first symptoms and diagnosis
was 28 months. Misdiagnoses occurred in 6 of the 12 cases (50%): osteoblastoma, chondroblastoma,
chondrosarcoma, osteoid osteoma, desmoid fibroma, and osteomyelitis were, respectively,
the initial diagnoses. Histologically, 5 of the 12 tumors (42%) were low-grade lesions.
Four of the seven patients with a highgrade tumor died of metastatic disease after
a mean survival of 50 months. Eight patients are alive with no evidence of disease
after a mean follow-up of 162 months.
When a painful swelling in a bone of the foot is observed, even if numerous benign
conditions (such as fractures, infections, or benign bone tumors) are far more likely
to occur, osteosarcoma must be ruled out to avoid delays in the treatment. Osteosarcomas
of the foot may easily be misdiagnosed, especially because they almost always occur
in adults, in contrast to osteosarcomas in general. High-grade tumors of the foot
are as aggressive as other osteosarcomas and should be managed accordingly—with use
of a safe-margins surgical procedure and chemotherapy.