ABSTRACT
PURPOSE: The purpose of this study was to evaluate the oncologic outcomes of parosteal osteosarcoma (POS) and to ascertain the fates of patients after local recurrence (LR). MATERIALS AND METHODS: The authors retrospectively reviewed 22 POS patients with an average follow-up of 114 months (range: 36-235 months). Seven of the 22 patients were referred after LR. There were 17 Stage IB and 5 Stage IIB (G2, 2; dedifferentiation, 3). Tumors were located in the femur (11) and in other locations (11). Initial surgical margins were wide in 10, marginal in 5, and intralesional in 7. Correlations between clinico-pathologic variables and LR and clinical courses after LR were evaluated. RESULTS: The 10-year overall survival rate was 85.7%. Three (14%) patients developed distant metastasis and all of them succumbed to the disease. Nine (41%) patients developed LR. Tumor location, resection type, and surgical margin were found to be correlated with LR. At final follow-up, 7 of the 9 patients that experienced local failure achieved no evidence of disease. CONCLUSION: A substantial risk of misdiagnosis exists, especially for POS in other than a femoral location. Recurrent tumor re-excision is possible in most cases; however, patients with an aggressive recurrence pattern deserve special attention.