Fig. 1

MRI characteristics of the diffuse gliomas in the 6 new enchondromatosis patients and double staining with anti-IDH1R132H and anti-ATRX antibodies. Top: MRI findings of patient 1 to patient 6 at diagnosis (axial T2/fluid-attenuated inversion recovery (FLAIR) sequences) demonstrating multicentric tumors in patients 1, 2, 3 and 4. Bottom: histological characteristics of the recurrent tumor of patient 3. a Hematoxylin eosin staining demonstrating an anaplastic glioma. b IDH1 R132H expression (brown signal). c Diffuse loss of ATRX expression in tumor cells and maintained expression (brown signal) in endothelial cells. d-g) Double staining demonstrating rare cells with a normal oligodendrocyte (black arrowheads) or astrocyte (black arrows) morphology expressing both IDH1 R132H (red signal) and ATRX (brown signal) (inserts showing same cells at higher magnification) and tumor cells with abnormal morphology and expressing IDH1 R132H but not ATRX (white arrows)