Fig. 1

Imaging characteristics of the brain and spinal lesions; pathological hallmarks of the spinal lesion. a-d, MRI of the case. Axial T2-weighted images show the well circumscribed lesion located within the cavernous sinus (a), at the level of the ganglion of the trigeminal nerve measuring 20 × 9 mm close to the not invaded internal carotid (red arrow) and associated with bilateral asymmetric lesions (b), measuring 14 × 12 mm in the interpedoncular fossa and 11 × 10 mm in the cerebellopontine angle within the ganglia of cranial nerves VII and VIII respectively (red arrows) and a nodule at the L3 level (c). T2 weighted axial plane of the cerebellum displaying exaggerated foliation of the right hemispheric cerebellar cortex (white arrow) located close to the vermis (d). e-h, histopathology of the resected L3 lesion. Histological view shows all but disorganized components of a spinal ganglion (e), including often dysmorphic ganglion cells (red arrow) and astrocytes (green arrow) lying in a fibrillar background [OM × 200]. Immunohistochemistry displays multiple GFAP positive astrocytes [OM × 200] (f), and numerous MAP2 positive ganglion cells [OM × 200] (g). PTEN immunolabeling reveals immunoreactive astrocytes (green arrow), endothelial (red arrow) and satellite cell nuclei, whereas positivity of ganglion cell (black arrow) nuclei is lost [OM × 100] (h). (OM: original magnification)