1 Preoperative gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) and computed tomography (CT) of the thoracic spine. a MRI in the coronal orientation, b MRI in the sagittal orientation, and c MRI in the axial orientation showing an intradural extramedullary tumor with dural tail sign located on the left and dorsal sides at the T10-T11 level, compressing the spinal cord severely. d Sagittal reconstruction CT shows extensive peripheral calcification of the tumor Surgery was performed under transcranial electrical stimulation of motor evoked potentials for spinal cord monitoring.