title: Secondary aneurysmal bone cyst in the distal humerus after resection of intra-articular nodular fasciitis of the elbow.
abstract: BACKGROUND
  Nodular fasciitis most often occurs within subcutaneous tissues, but may also arise within skeletal muscle, dermis, vessels, peripheral nerves and, although rarely, within joints. Knowledge regarding the cause of aneurysmal bone cysts, its natural history, and the results of treatment is limited. Secondary aneurysmal bone cysts are associated with other neoplastic processes. Intra-articular nodular fasciitis in the elbow joint has not been reported previously, nor has the development of aneurysmal bone cyst secondary to intra-articular nodular fasciitis in the elbow joint.
  
  
  METHODS
  We report an unusual case of a Japanese 13-year-old boy who presented with a 1-year history of right elbow pain. The onset of pain was insidious, without antecedent trauma. On physical examination, the range of motion of the elbow was limited. Grip strength was reduced in the affected extremity. Incisional biopsy was performed and histologic findings revealed nodular fasciitis in the elbow joint. After tumor excision, a secondary aneurysmal bone cyst in the distal humerus developed. Endoscopy-assisted curettage and artificial bone grafting were performed. One year after surgery, a plain radiography showed no recurrence, and the patient returned to his daily activities without any symptoms.
  
  
  CONCLUSIONS
  An aneurysmal bone cyst in the distal humerus developed after excision of intra-articular nodular fasciitis arising in the elbow. The secondary aneurysmal bone cyst successfully healed after endoscopy-assisted curettage and artificial bone grafting. The findings of this case suggest that these two tumors reside in the same biologic spectrum defined as USP6-induced tumors.
authors.affiliation: Department of Hand Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan. michi-ya@med.nagoya-u.ac.jp.
authors.forename: Michiro
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan. urakawa@med.nagoya-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Urakawa
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan. ynishida@med.nagoya-u.ac.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nishida
authors.affiliation: Department of Hand Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan. h-hirata@med.nagoya-u.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hirata
mesh_terms: D000293:Adolescent; D017824:Bone Cysts, Aneurysmal / Q000150:complications* / Q000175:diagnosis*; D016025:Bone Transplantation; D004550:Elbow / Q000473:pathology; D004551:Elbow Joint / Q000473:pathology*; D004724:Endoscopy; D005208:Fasciitis / Q000150:complications* / Q000601:surgery*; D006801:Humans; D007564:Japan; D008279:Magnetic Resonance Imaging; D008297:Male; D010146:Pain; D014057:Tomography, X-Ray Computed