title: Primary epidural hemangiopericytoma in the lumbar spine: a case report.
abstract: METHODS
  A case report of primary epidural hemangiopericytoma in the lumbar spine and a review of the literature are presented.
  
  
  OBJECTIVE
  To present the result of pathologic diagnosis using immunohistochemical staining and the treatment of spinal hemangiopericytoma.
  
  
  BACKGROUND
  Spinal hemangiopericytoma is a very rare soft tissue tumor with specific pathologic features and a clinical course featuring high rates of recurrence and metastasis.
  
  
  METHODS
  A 39-year-old woman reported numbness in both legs. Neither sensory abnormalities nor muscle weakness was present in her lower extremities. Magnetic resonance imaging showed a tumor dorsal to the thecal sac at L1-L2. After L1 and L2 laminectomy, the tumor with its dural base was resected en bloc.
  
  
  RESULTS
  The patient's clinical and neurologic symptoms disappeared after surgery. Microscopic examination showed oval- or spindle-shaped cells with slightly acidic cytoplasm and oval nuclei. Silver staining emphasized fibers around tumor cells. The test results for the tumor cells were positive for vimentin staining, but negative for alpha-TM staining using thrombomodulin, a marker for endothelial cells. On the basis of these pathologic findings, the tumor was diagnosed as a hemangiopericytoma, a type of tumor composed of mesenchymal hemangiopericytes. Neither recurrence nor metastasis of the tumor was found during the 2-year follow-up period after surgery.
  
  
  CONCLUSIONS
  Soft tissue hemangiopericytoma is a well-recognized entity considered to be an aggressive neoplasm with a high rate of recurrence and a propensity to metastasize. Immunohistochemical investigation was essential for the diagnosis of this tumor. Although hemangiopericytoma very rarely occurs in the spine, surgeons treating patients with this tumor should be aware of its metastatic potential.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, Kagoshima University, Japan.
authors.forename: Kosei
authors.initials: K
authors.lastname: Ijiri
authors.forename: Shinya
authors.initials: S
authors.lastname: Yuasa
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yone
authors.forename: Shunji
authors.initials: S
authors.lastname: Matsunaga
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ryoki
authors.forename: Noboru
authors.initials: N
authors.lastname: Taniguchi
authors.forename: Suguru
authors.initials: S
authors.lastname: Yonezawa
authors.forename: Setsuro
authors.initials: S
authors.lastname: Komiya
mesh_terms: D000328:Adult; D000792:Angiography; D015415:Biomarkers / Q000032:analysis; D015174:Epidural Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006393:Hemangiopericytoma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging; D016622:Silver Staining; D014746:Vimentin / Q000032:analysis / Q000276:immunology
chemical_list: D015415:Biomarkers; D014746:Vimentin