title: Thoracic myelopathy due to an intramedullary herniated nucleus pulposus:  first case report and review of the literature.
abstract: BACKGROUND
  Herniation of intervertebral discs is relatively common. Migration usually occurs in the ventral epidural space; very rarely discs migrate in the subdural space. No cases of intradural intramedullary disc have been reported in humans.
  
  
  METHODS
  A case of a herniated intervertebral disc directly into the spinal cord parenchyma is presented. The patient presented with 2 weeks of progressive bilateral lower extremity numbness and weakness, saddle hypoesthesia, urinary dysfunction and gait disturbance. Spine magnetic resonance imaging (MRI) with gadolinium revealed a solitary well-defined intramedullary lesion (T7-T8 level) with ring enhancement and focal cord expansion with significant surrounding edema. Metastatic workup and neural axis imaging was negative. A thoracic laminectomy and myelotomy was performed; the lesion was pearlescent and well circumscribed. It was densely adherent to the ventral pia and gross totally removed. Pathology was consistent with nucleus pulposus.
  
  
  CONCLUSIONS
  Intradural intramedullary migration of a herniated intervertebral disc is extremely rare but should be considered in the differential. It may present in a variety of clinical scenarios, including thoracic myelopathy, and mimic intramedullary spinal cord tumor.
authors.affiliation: Department of Neurosurgery, Thomas Jefferson University Hospital, Philadelphia, PA, USA.
authors.forename: Sonia
authors.initials: S
authors.lastname: Teufack
authors.forename: Peter
authors.initials: P
authors.lastname: Campbell
authors.forename: Pranshu
authors.initials: P
authors.lastname: Sharma
authors.forename: Tim
authors.initials: T
authors.lastname: Lachman
authors.forename: Lawrence
authors.initials: L
authors.lastname: Kenyon
authors.forename: James
authors.initials: J
authors.lastname: Harrop
authors.forename: Srinivas
authors.initials: S
authors.lastname: Prasad
mesh_terms: D000368:Aged; D004824:Epidural Space / Q000473:pathology; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000150:complications*; D007796:Laminectomy / Q000379:methods*; D008279:Magnetic Resonance Imaging; D013118:Spinal Cord Diseases / Q000209:etiology* / Q000601:surgery*