title: [Extra-articular localization of nodular synovitis: a case report].
abstract: BACKGROUND
  The extra-articular nodular synovitis is regarded as a rare case of the common pigmented villonodular synovitis. The following report points out a case with wide extension in a young man's proximal lower leg.
  
  
  METHODS
  A 24-year-old man complained about a non-painful tumor at his left proximal lower leg without any clinical handicap. Some years before he got a fracture of the proximal left tibia caused by an adequate sports trauma. So he had to undergo two operative investigations. The radiographs showed a transparent soft tissue tumor, which displaced the corticalis of the bone for some centimeters. The magnetic resonance imaging did not hint at a malignant process. After operative treatment the diagnosis was confirmed by histology.
  
  
  CONCLUSIONS
  By operative and histological investigation advice could given to a benign tumor. The etiology of the extra-articular nodular synovitis is to be regarded as unknown. In our case a dislocation of synovial cells to extra-articular should be discussed.
authors.affiliation: Klinik und Poliklinik für Orthopädie, Universität Bonn.
authors.forename: F
authors.initials: F
authors.lastname: Gassel
authors.forename: T
authors.initials: T
authors.lastname: Wallny
authors.forename: U A
authors.initials: UA
authors.lastname: Wagner
authors.forename: E
authors.initials: E
authors.lastname: Wardelmann
authors.forename: K
authors.initials: K
authors.lastname: Tschubel
authors.forename: O
authors.initials: O
authors.lastname: Schmitt
mesh_terms: D000328:Adult; D001265:Athletic Injuries / Q000150:complications; D003937:Diagnosis, Differential; D006801:Humans; D007869:Leg Injuries / Q000150:complications*; D008297:Male; D012983:Soft Tissue Neoplasms / Q000175:diagnosis; D013586:Synovitis, Pigmented Villonodular / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology / Q000601:surgery; D013978:Tibial Fractures / Q000150:complications; D013997:Time Factors; D014057:Tomography, X-Ray Computed