A Radiological Scoring System for Differentiation between Enchondroma and Chondrosarcoma.

Background: It is challenging to differentiate between enchondromas and atypical cartilaginous tumors (ACTs)/chondrosarcomas. In this study, correlations between radiological findings and final diagnosis were investigated in patients with central cartilaginous tumors.

Methods: To evaluate the diagnostic usefulness of radiological findings, correlations between various radiological findings and final diagnoses were investigated in a cohort of 81 patients. Furthermore, a new radiological scoring system was developed by combining radiological findings.

Results: Periosteal reaction on X-ray ( = 0.025), endosteal scalloping ( = 0.010) and cortical defect ( = 0.002) on CT, extraskeletal mass ( < 0.001), multilobular lesion ( < 0.001), abnormal signal in adjacent tissue ( = 0.004) on MRI, and increased uptake in bone scan ( = 0.002) and thallium scan ( = 0.027) was significantly correlated with final diagnoses. Based on the correlations between each radiological finding and postoperative histological diagnosis, a radiological scoring system combining these findings was developed. In another cohort of 17 patients, the sensitivity, specificity, and accuracy of the radiological score rates for differentiation between enchondromas and ACTs/chondrosarcomas were 88%, 89%, and 88%, respectively ( = 0.003).

Conclusion: Radiological assessment with combined radiological findings is recommended to differentiate between enchondromas and ACT/chondrosarcomas.