Chondroblastic osteosarcoma: characterisation by gadolinium-enhanced MR imaging correlated with histopathology

Objective. To identify specific features of chondroblastic osteosarcoma on gadopentetate dimeglumine (Gd)-enhanced magnetic resonance (MR) imaging. Design and patients. Nine patients with chondroblastic osteosarcoma and a control group of 20 patients with conventional central osteosarcoma were included in this study. The histopathological findings of the surgical specimens were compared with enhancement patterns on static Gd-enhanced MR images. Results. In chondroblastic osteosarcoma septonodular and peripheral rim enhancement represented tumour with a pure chondroid matrix. Non-enhancing and heterogeneous enhancing areas represented tumour with both chondroid and osteoid matrix. In the tumours in the control group enhancement was predominantly heterogeneous but in one it was homogeneous. All these areas corresponded to necrotic or viable osteoid tumour tissue or fibrovascular tissue in areas of necrosis. Conclusion. Gd-enhanced MR imaging can assist in obtaining diagnostic biopsy material of chondroblastic osteosarcoma by identifying both osteoid-and chondroid-forming areas.