Chondroblastoma of extra-craniofacial bones: Clinicopathological analyses of 103 cases

We elucidated clinicopathological characteristics of chondroblastoma (CB) in Japan, and reliable clinicopathologic parameters predicting local recurrence and/or metastasis. Clinicopathological profiles of 103 CB (80 male, 23 female) in extra-craniofacial bones were retrieved. Numerical scoring of nine pathological and five radiological features was statistically analyzed to determine prognostic significance. Age ranged 8-61 years (average 19.6 years). Frequently involved sites were femur, tibia, calcaneus, patella and humerus. Radiologically, tumors were 2-80 mm (average 31.1 mm) in size. Marginal sclerosis and calcification were common. Histologically, pink cartilage, mitoses, and chicken-wire calcification were often seen. Within a follow-up period [2-260 months (average 53.5 months)], the local recurrence rate was 15.5%. No patient had metastasis. Recurrence was most frequently observed at the femur. By log-rank analysis, only cyst formation in images was significant for predicting recurrence free survival (RFS). By Cox hazard analysis with representative clinico-radiological and pathological features, only age (≥16 years) and cyst formation were significant predictors for RFS. Pathological features were not significant in both uni- and multivariate analyses.