title: A case report of atypical long segmental thoracic hypertrophic pachymeningitis with ossification of ligamentum flavum and literature review.
abstract: Thoracic spinal stenosis caused by ossification of ligamentum flavum (OLF) is frequently seen, but long segmental thoracic spinal cord compressed by consequent thickened ligament posteriorly was rarely reported.
  
  
  
  To report a case of thoracic spinal cord compression caused by atypical long segmental thoracic hypertrophic pachymeningitis (HP) with OLF.
  
  
  
  A 55-year-old woman presenting with weakness and numbness in lower extremities was admitted to our department. Combined with physical examination and MRI results, diagnosis of HP with OLF was considered. Due to progressive neurological symptoms, thoracic decompression with internal fixation was performed.
  
  
  
  The patient felt a reduced numbness and improvement in motor functions 5 days after surgery. Pathological examination suggested the diagnosis of HP with OLF.
  
  
  
  HP is a rare condition characterized as thickening and enhancement of the dura mater on contrast-enhanced MRI and chronic inflammatory hyperplasia changes on biopsy. A case of atypical HP complicated with OLF is described. Chondrocytes infiltration in histological examination indicates the potential of ossification in HP.
authors.affiliation: Department of Orthopedics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Jiefang Street N88, Hangzhou, Zhejiang, China. tangruofu@qq.com.
authors.forename: Ruofu
authors.initials: R
authors.lastname: Tang
authors.affiliation: Department of Orthopedics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Jiefang Street N88, Hangzhou, Zhejiang, China.
authors.forename: Fangcai
authors.initials: F
authors.lastname: Li
authors.affiliation: Department of Orthopedics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Jiefang Street N88, Hangzhou, Zhejiang, China.
authors.forename: Qixin
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000328:Adult; D019299:Decompression, Surgical / Q000379:methods; D004388:Dura Mater / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D006801:Humans; D017843:Ligamentum Flavum / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008581:Meningitis / Q000150:complications* / Q000000981:diagnostic imaging; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology; D013117:Spinal Cord Compression / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D014057:Tomography, X-Ray Computed
keywords: Hypertrophic pachymeningitis; Myelopathy; Ossification of ligamentum flavum; Thoracic spine