Intramedullary Cavernoma with Hematomyelia and Unusual Clinical Findings of Brown-Sequard Syndrome: A Case Report

We aim to report an extremely rare case of a primary thoracic intramedullary cavernoma with Brown-Sequard syndrome (BSS), its transcranial magnetic stimulation (TMS)/somatosensory evoked potential (SSEP) neurophysiology tests, and their localizing value. A 53-year-old Chinese male with a history of multiple arteriovenous malformations (AVMs) presented with an intermittent 3-year history of the left lower limb weakness with recent worsening and findings of dissociated sensory loss. Neurophysiological testing showed prolonged central motor conduction time to his left lower limb on TMS while tibial SSEP showed prolonged P37 latencies. Magnetic resonance imaging spine showed a T4-5 intramedullary expansile enhancing cord lesion, suggestive of a thoracic cavernoma, with surrounding acute hematomyelia and cord edema from C7 to T6. A spinal angiogram did not reveal any vascular malformation. He was conservatively treated for possible T4-5 cavernoma with hematomyelia. Repeat imaging showed complete resolution of edema with a T3-5 internal T2-weighted hyperintensity and residual susceptibility focus likely representing a cavernoma that had bled with no evidence of AVM. A repeat tibial SSEP still showed prolonged tibial SSEPs, but TMS was now normal. Primary thoracic intramedullary cavernomas may be a rare cause of BSS. TMS and SSEP may have a role in the diagnostic evaluation of BSS.