title: Intramedullary Recurrence of a Thoracic Meningioma-Presentation of an Unusual Case and Review of the Literature.
abstract: BACKGROUND
  Spinal meningiomas are typically extra-axial, slow-growing, benign tumors that arise from the arachnoid cap cells. Intramedullary spinal meningiomas are exceedingly rare with few cases reported in the literature.
  
  
  METHODS
  A 64-year-old man with a history of grade I thoracic meningioma at the T4 level resected initially in 1989 and who required reoperation in 2013 for intradural, extramedullary recurrence of tumor presented again in 2015 with gait difficulty. Magnetic resonance imaging revealed a soft tissue mass at the T3 to T4 levels on the left side of the canal that was mildly enhancing on T1 contrasted sequences. The patient was taken to the operating room, where a purely intramedullary recurrence was discovered without extramedullary extension or a dural-based attachment. The intramedullary tumor was completely resected, and postoperatively the patient recovered well and was at his neurologic baseline. The patient ultimately underwent proton beam radiotherapy because this tumor, although benign, had recurred twice.
  
  
  CONCLUSIONS
  Intramedullary spinal meningiomas, particularly intramedullary low-grade recurrence of a previously extramedullary tumor, are rare phenomena. Although the pathogenic mechanisms are not well understood, intramedullary recurrence as described in this patient may reflect extrinsic factors related to prior surgical resections in addition to histologic progression. When operating on recurrent extramedullary lesions, aggressive arachnoid dissection may predispose patients to unusual patterns of recurrence.
authors: Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA. Electronic address: Matthew.Piazza@uphs.upenn.edu.
authors: Matthew A
authors: MA
authors: Piazza
authors: Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors: Ashwin G
authors: AG
authors: Ramayya
authors: Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors: Geoffrey A
authors: GA
authors: Geiger
authors: Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors: Michelle
authors: M
authors: Alonso-Basanta
authors: Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors: MacLean P
authors: MP
authors: Nasrallah
authors: Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors: William C
authors: WC
authors: Welch
authors: Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors: Ali K
authors: AK
authors: Ozturk
mesh_terms: D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008579:Meningioma / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D013120:Spinal Cord Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D013904:Thoracic Vertebrae / Q000473:pathology*
keywords: Intradural; Intramedullary; Meningioma; Recurrence; Spine; Thoracic; Tumor