Imaging differences between enchondroma and atypical cartilaginous tumor: Insights from a reference center

Differentiating enchondromas from atypical cartilaginous tumors (ACTs) is crucial for optimal patient management, as ACTs often require surgical intervention or surveillance, whereas enchondromas are typically managed conservatively. This study aims to identify imaging markers that aid in distinguishing these entities through a comprehensive analysis of radiographic and magnetic resonance imaging (MRI) features. This retrospective study included 50 patients diagnosed with ACT or enchondroma between 2013 and 2024. Imaging variables analyzed included tumor size, lobulation, matrix calcification, endosteal scalloping, periosteal reaction, cortical expansion, fat entrapment, T2-weighted hypersignal, heterogeneity, and cortical discontinuity. The distribution in short and long bones was also assessed. Statistical analysis used the Chi-square test for categorical variables and the Kruskal-Wallis test for continuous variables. Regarding final diagnosis, most patients had enchondromas (72 %, n = 36), followed by ACTs (20 %, n = 10) and chondrosarcomas (8 %, n = 4). ACTs showed a significant increase in tumor size and a preference for long bones (p < 0.05) compared to enchondromas. Endosteal scalloping demonstrated a strong trend toward significance (p = 0.051). Other radiologic characteristics had no significant difference. Tumor size and endosteal scalloping emerge as key markers in differentiating ACTs from enchondromas. However, the limited sample size and borderline statistical significance in some variables highlight the need for further research.