title: Osteoid osteoma and osteoid osteoma-mimicking lesions: biopsy findings, distinctive MDCT features and treatment by radiofrequency ablation.
abstract: OBJECTIVE
  To report the biopsy findings of osteoid osteoma (OO) and OO-mimicking lesions, assess their distinctive multidetector computed tomography (MDCT) features and evaluate treatment by radiofrequency ablation (RFA).
  
  
  METHODS
  In this multicentric retrospective study, 80 patients (54 male, 26 female, mean age 24.1 years, range 5-48) with presumed (clinical and MDCT features) OO were treated by percutaneous RFA between May 2002 and June 2009. Per-procedural biopsies were always performed. The following MDCT features were assessed: skeletal distribution and location within the bone, size, central calcification, surrounding osteosclerosis and periosteal reaction. Clinical success of RFA was evaluated.
  
  
  RESULTS
  Histopathological diagnoses were: 54 inconclusive biopsies, 16 OO, 10 OO-mimicking lesions (5 chronic osteomyelitis, 3 chondroblastoma, 1 eosinophilic granuloma, 1 fibrous dysplasia). OO-mimicking lesions were significantly greater in size (p = 0.001) and presented non-significant trends towards medullary location (p = 0.246), moderate surrounding osteosclerosis (p = 0.189) and less periosteal reaction (p = 0.197), compared with OO. Primary success for ablation of OO-mimicking lesions was 100% at 1 month, 85.7% at 6 and 12 months, and 66.7% at 24 months. Secondary success was 100%.
  
  
  CONCLUSIONS
  Larger size, medullary location, less surrounding osteosclerosis and periosteal reaction on MDCT may help differentiate OO-mimicking lesions from OO. OO-mimicking lesions are safely and successfully treated by RFA.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, Rue du Bugnon 46, 1011, Lausanne, Switzerland.
authors.forename: Fabio
authors.initials: F
authors.lastname: Becce
authors.forename: Nicolas
authors.initials: N
authors.lastname: Theumann
authors.forename: Antoine
authors.initials: A
authors.lastname: Rochette
authors.forename: Frédérique
authors.initials: F
authors.lastname: Larousserie
authors.forename: Raphaël
authors.initials: R
authors.lastname: Campagna
authors.forename: Stéphane
authors.initials: S
authors.lastname: Cherix
authors.forename: Louis
authors.initials: L
authors.lastname: Guillou
authors.forename: Elyazid
authors.initials: E
authors.lastname: Mouhsine
authors.forename: Philippe
authors.initials: P
authors.lastname: Anract
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Drapé
authors.forename: Antoine
authors.initials: A
authors.lastname: Feydy
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001706:Biopsy; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010017:Osteoma, Osteoid / Q000175:diagnosis* / Q000532:radiotherapy*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
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