Prediction of the nature of centromedullary cartilage tumours from imaging : retrospective observational study of 127 tumours ; Prédiction de la nature des tumeurs cartilagineuses endosseuses à partir de l’imagerie : étude rétrospective observationnelle de 127 tumeurs

Introduction: The challenge of establishing diagnostic hypotheses on imaging is essential for therapeutic management, which differs according to histological type. Presently, imaging criteria most often allow differentiation between high-grade chondrosarcomas (CS) and chondromas (Ch), and less frequently between atypical cartilage tumors/grade 1 chondrosarcomas (ACT/CS1), although treatment differs. Material and methods: Retrospective observational study between 2004 and 2020 of the Ch and CS of an expert center of bone tumors in Toulouse. Inclusion of all patients with a pathological diagnosis of Ch, atypical cartilage tumor/chondrosarcoma grade 1 (TCA/CS1), chondrosarcoma grade 2 (CS2) or chondrosarcoma grade 3 (CS3) with at least one MRI or CT scan in the PACS. Blinded imaging reading of histological diagnosis by two radiologists.Results: 127 CTs were included, 59 Ch and 68 CS including 19 TCA/CS1, 35 CS2 and 14 CS3. Location was an important feature: All TCs of the small long bones hands were Ch and those of the pelvis and ribs were CS. 83% (5/6) of scapular TCs and 60% (6/10) of TCs of the feet were CS. On the humerus 60.6% (20/33) were Ch and on femurs 63% (22/35) were CS. The significant characteristics of the CS group were (p<0.05): age, male gender, epiphyseal topography of the appendicular skeleton, large size, extension of endosteal erosions >2/3 of the major tumor axis, cortical and soft tissue invasion, cortical thickening, periosteal reaction, extension of calcifications <1/3 of the tumor, soft tissue edema, bone marrow edema and periostitis, intra-tumoral T1 hypersignal areas and peripheral and confluent enhancement. In the Ch group: female gender, absence of endosteal erosions or erosions <1/3 of the cortical thickness, residual bone marrow islands and arc and ring enhancement. In the TCA group the features were the same as CS except for epiphyseal topography, depth of erosions, T1 hypersignal and peripheral enhancement. Conclusion: This study highlights the known imaging criteria for ...