SMALL-CELL OSTEOSARCOMA OF BONE - REVIEW OF 72 CASES

BACKGROUND. Small cell osteosarcoma of bone is a rare form of osteosar coma, with an incidence rate of 1.3%. This tumor must be differentiate d from other small cell malignancies because of treatment consideratio ns, particularly patient response to chemotherapy. METHODS. Clinicopat hologic findings in 72 cases (22 from Mayo Clinic files and 50 from co nsultation files) of small cell osteosarcoma of bone were studied. RES ULTS. The femur was the most common bone involved, although the tumor was found in all portions of the skeleton. Radiographic features (avai lable in 35 cases) suggested a diagnosis of osteosarcoma in 20 cases, Ewing's sarcoma or lymphoma in 14 cases, and giant cell tumor in 1 cas e. Histologically, there were four types according to the predominant cell size and cytologic features. Osteoid production was identified in all tumors. Complete treatment and follow-up data were available for 45 cases. Generally, in those cases without surgical treatment, greate r than 60% of patients died of disease within 2 years. If the surgical procedure was associated with a marginal tumor margin, the prognosis was poor. In the 30 patients with wide or radical surgical margins, at last follow-up 13 were alive with no evidence of disease, 2 were aliv e with disease, and 15 died of disease at 5 months to 13.1 years after diagnosis. In 16 of 22 Mayo Clinic patients, excluding those who pres ented with metastasis, the cumulative 5-year survival rate was 28.9%. Median survival time in patients who had surgery with additional chemo therapy was 13.4 years, compared with 1.4 years in patients who underw ent surgery alone (P = 0.17). CONCLUSIONS. Small cell osteosarcoma is a definite reproducible histologic entity. Treatment should be based o n a protocol for osteosarcoma. (C) 1997 American Cancer Society.