title: Hemangiopericytomas in the spine: clinical features, classification, treatment, and long-term follow-up in 26 patients.
abstract: BACKGROUND
  Intraspinal hemangiopericytoma (HPC) is a rare and malignant extra-axial tumor with a strong tendency to recur and metastasize. There is a paucity in the literature of large case series of patients with intraspinal HPCs.
  
  
  OBJECTIVE
  We retrospectively analyzed the clinical radiological and histological features, classification, and treatment of 26 patients with HPCs in the spine.
  
  
  METHODS
  Twenty-six patients with HPCs in the spine were treated at our institution between 1987 and 2010. Medical records were reviewed retrospectively to collect data on the clinical features, tumor morphology, surgical resection, recurrence, and follow-up.
  
  
  RESULTS
  The 26 patients were predominantly male, and the mean age at diagnosis was 33.8 years. The intraspinal HPCs were divided into 3 types and 5 subtypes. Most of them involved the neighboring segments and/or caused bony erosion. All tumors were immunohistochemically positive for vimentin and negative for epithelial membrane antigen. All patients underwent at least 1 surgery, and most of them received postsurgical radiotherapy. The 5-year Kaplan-Meier rate of survival was 76%. The 5-year recurrence-free rate of survival was 29.4%. Only the tumor pathological grade was significantly associated with survival time and recurrence.
  
  
  CONCLUSIONS
  High-grade tumors had a shorter survival time and recurred earlier than low-grade tumors. Surgical removal and postoperative radiotherapy are critical for the treatment of intraspinal HPCs. However, total resection may not necessary for these tumors. Stereotactic radiosurgery may be a good alternative to control the recurrent lesions.
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Huan-guang
authors.initials: HG
authors.lastname: Liu
authors.forename: An-chao
authors.initials: AC
authors.lastname: Yang
authors.forename: Ning
authors.initials: N
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Xiao-guang
authors.initials: XG
authors.lastname: Qiu
authors.forename: Jian-guo
authors.initials: JG
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D059186:Chemoradiotherapy, Adjuvant; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006393:Hemangiopericytoma / Q000145:classification / Q000473:pathology* / Q000628:therapy*; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D019635:Neurosurgical Procedures; D016634:Radiosurgery; D013120:Spinal Cord Neoplasms / Q000145:classification / Q000473:pathology* / Q000628:therapy*; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult