Résumé
PURPOSE: Giantcell-rich osteosarcoma (GCRO) is a rare subtype of osteosarcoma. We reviewed; 1) radiological finding of GCRO and clinical impression-related diagnostic workup at referral center, 2) diagnostic delay until a proper diagnosis is made, 3) impact of diagnostic delay on the oncologic outcome. MATERIALS AND METHODS: We reviewed 17 patients with GCRO. We investigated the plain radiographic finding, tumor size and location, presence of pathologic fracture, clinical impression and pathological diagnosis at referral center, diagnostic delay, definitive treatment, local recurrence, metastasis, and survival rate. RESULTS: Eleven cases (64.7%) showed a plain radiographically, purely osteolytic pattern while 6 cases (35.3%) showed mixed osteolytic and sclerotic lesion. Diagnosis at primary center was osteosarcoma in 7 (41.2%), giant cell tumor in 7 (41.2%), and benign bone tumor in 3 (17.6%). Six patients (35.3%) experienced diagnostic delay. Mean diagnostic delay was 3.1 months (1 to 8). At final follow-up 5-year actuarial survival rate of 17 patients was 65%+/-25%. Although 11 patients without diagnostic delay showed a tendency of high survival over 6 patients with diagnostic problem, there was no statistical significance (p=0.14). CONCLUSION: GCRO is a rare subtype of osteosarcoma simulating giant cell tumor both pathologically and radiologically. Careful diagnostic approach is required in order not to misdiagnose this malignant tumor.