Fig. 1

Radiological features. Case #1 A Axial FLAIR brain MRI shows a hyperintense infiltrative lesion of the right thalamus extended to the right lateral ventricle. B Axial contrast-enhanced T1-weighted brain MRI shows a heterogeneous enhancement after gadolinium injection. C Axial T2-weighted brain MRI shows other nodular FLAIR hyperintensities of the cerebellum (arrows). D Sagittal T2-weighted spine MRI shows a hyperintense peripheral lesion of the spinal cord (arrow). Case #2 E Axial FLAIR-weighted brain MRI shows a hyperintense lesion of the right thalamus extended to the third ventricle and the right hippocampus. F Axial contrast-enhanced T1-weighted brain MRI shows a heterogeneous enhancement of this lesion. G Axial contrast-enhanced T1-weighted brain MRI shows an intraventricular localization in the fourth ventricle (arrow). H Sagittal contrast-enhanced T1-weighted spine MRI shows multiple spinal leptomeningeal lesions. Case #3 I Sagittal T2-weighted spine MRI shows a thoracic hyperintense leptomeningeal lesion. J Sagittal T2-weighted lumbar MRI shows multiple lumbar intradural lesions, attached to nerve roots and in the lower end of the dural sac. K Sagittal and L Axial contrast-enhanced T1-weighted lumbar MRI show an enhancement of these lesions. FLAIR: Fluid Attenuated Inversion Recovery