title: Tenosynovial Giant Cell Tumor, Diffuse Type/Pigmented Villonodular Synovitis in a Pars Defect: A Case Report.
abstract: METHODS
  Case report.
  
  
  OBJECTIVE
  To describe a rare case of tenosynovial giant cell tumor, diffuse type/pigmented villonodular synovitis (PVNS) in a pars defect in a patient with lumbar spondylolysis.
  PVNS rarely occurred in lumbar spine, and no studies in the English literature have reported PVNS in a pars defect in lumbar spondylolysis.
  
  
  METHODS
  The patient was a 14-year-old female presented with a 5-month history of low back pain. Plain radiography showed spondylolysis at L5 and computed tomography revealed a 1 × 2-cm slightly eroding tumorous mass at the left L5 pars. On magnetic resonance imaging, the mass showed intermediate intensity and gadolinium enhancement on T1-weighted images (WI) and high intensity on T2-WI and T2 STAR-WI. After undergoing computed tomography-guided needle biopsy, a pathological diagnosis of PVNS was made and total gross resection was performed.
  
  
  RESULTS
  The gross appearance and the postoperative pathological diagnosis were consistent with PVNS. The postoperative clinical course was uneventful and postoperative computed tomography and magnetic resonance imaging revealed no residual lesion.
  
  
  CONCLUSIONS
  This is the first report of PVNS occurring in spondylolysis.
  
  
  METHODS
  N/A.
authors.affiliation: From the Departments of *Orthopedics and †Radiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, Japan; and ‡Department of Orthopedics, National Kochi Hospital, Kochi, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kimura
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Nishisho
authors.forename: Toshinori
authors.initials: T
authors.lastname: Sakai
authors.forename: Ryo
authors.initials: R
authors.lastname: Miyagi
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Takao
authors.forename: Seiji
authors.initials: S
authors.lastname: Iwamoto
authors.forename: Kosaku
authors.initials: K
authors.lastname: Higashino
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Takata
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Goda
authors.forename: Shunichi
authors.initials: S
authors.lastname: Toki
authors.forename: Koichi
authors.initials: K
authors.lastname: Sairyo
mesh_terms: D000293:Adolescent; D003287:Contrast Media; D005260:Female; D018212:Giant Cell Tumor of Bone / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006801:Humans; D061705:Image-Guided Biopsy; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D011237:Predictive Value of Tests; D013125:Spinal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D013169:Spondylolysis / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D013586:Synovitis, Pigmented Villonodular / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media