Rare case of double migration of thoracic intradural schwannoma.

Mobile or migratory intradural extramedullary schwannoma have been reported many times in the lumbar levels, however only twice in cervical spine and six times in thoracic spine. Double migration was reported only once. The exact cause of the migration of a schwannoma arising from the nerve sheath of a spinal nerve root is unclear and especially mysterious in cervical and thoracic spine. We report a 49 year old male who presented with multiple sclerosis confirmed on brain MRI and CSF showing oligoclonal bands, with concomitant spinal myelopathy from a thoracic intradural extramedullary lesion. Serial MRIs showed rostral migration of lesion initially from T10 level to T6 and then caudally to T9 level on day of surgery. Intra operatively it was mobile with respirations and disconnected from any neural or vascular attachments. Histopathology confirmed a benign schwannoma with areas of necrosis. This is the rare occurrence of double migration of thoracic intradural schwannoma with possibility of tumor disconnection due to high dose steroid therapy for multiple sclerosis.