title: Arachnoid ossificans containing metaplastic hematopoietic marrow resulting in diffuse thoracic intrathecal cysts and severe myelopathy.
abstract: OBJECTIVE
  To present a rare case of multiple compressive thoracic intradural cysts with pathologic arachnoid ossification, review the literature and present the surgical options.                                                                        Few reports have identified the existence of arachnoid calcifications and intrathecal cysts causing progressive myelopathy. The literature regarding each of these pathologies is limited to case reports. Their clinical significance is not well studied, although known to cause neurologic sequelae.
  
  
  METHODS
  An 81-year-old female clinically presents with rapidly progressive myelopathy. Pre-operative magnetic resonance imaging identified multiple compressive thoracic intrathecal cysts. Surgical exploration and decompression of these cysts identified calcified plaques within the arachnoid. Histopathologic examination revealed fibrocalcific tissue undergoing ossification with bone marrow elements.
  
  
  RESULTS
  Due to progressive myelopathy, the thoracic cysts were decompressed and calcified plaques were excised, once identified intra-operatively.
  
  
  CONCLUSIONS
  On last examination, the patient's neurologic status had not improved, but had stabilized. The rate of neurologic improvement from excision and decompression is variable, but it may still be warranted in the face of progressive neurologic deficits.
authors: Department of Orthopedics, Stanford University Medical Center, Stanford, CA, USA. joshuahabrams@yahoo.com
authors: Joshua
authors: J
authors: Abrams
authors: Gordon
authors: G
authors: Li
authors: Stefan A
authors: SA
authors: Mindea
authors: Claudia M
authors: CM
authors: Haynes
authors: Ivan
authors: I
authors: Cheng
mesh_terms: D000369:Aged, 80 and over; D016080:Arachnoid Cysts / Q000473:pathology* / Q000601:surgery; D001853:Bone Marrow / Q000473:pathology*; D002114:Calcinosis / Q000473:pathology* / Q000601:surgery; D019299:Decompression, Surgical; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008679:Metaplasia / Q000473:pathology / Q000601:surgery; D009999:Ossification, Heterotopic / Q000473:pathology* / Q000601:surgery; D013118:Spinal Cord Diseases / Q000473:pathology* / Q000601:surgery; D013904:Thoracic Vertebrae / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome