title: Small sharp exostosis tip in solitary osteochondroma causing intermittent knee pain due to pseudoaneurysm.
abstract: BACKGROUND
  Complications of solitary or multiple osteochondromas are rare but have been reported in recent literature. Most reported complications arose in patients with multiple and/or sizable osteochondromas.
  
  
  METHODS
  A 22-year-old, female, Caucasian patient with obesity presented with intermittent knee pain and hematoma of the right calf. The MRI depicted a small, sharp exostosis tip of the dorsal distal femur with a surrounding soft-tissue mass. After profuse bleeding occurred during biopsy of the soft tissue mass, angiography revealed a pseudoaneurysm of the right popliteal artery. In a second-stage surgery the exostosis tip and pseudoaneurysm were resected.
  
  
  CONCLUSIONS
  Complications can also arise in small, seemingly harmless osteochondromas. Surgical resection should be considered as a preventive measure when exostoses form sharp tips close to neurovascular structures regardless of total osteochondroma size.
authors.affiliation: Department of Orthopedics and Tumor Orthopedics, University Hospital Muenster, Albert-Schweitzer-Campus 1, Building A1, 48149, Muenster, Germany. wiebke.guder@ukmuenster.de
authors.forename: Wiebke K
authors.initials: WK
authors.lastname: Guder
authors.forename: Arne
authors.initials: A
authors.lastname: Streitbürger
authors.forename: Georg
authors.initials: G
authors.lastname: Gosheger
authors.forename: Michael
authors.initials: M
authors.lastname: Köhler
authors.forename: Dagmar
authors.initials: D
authors.lastname: Bachhuber
authors.forename: Marcel-Philipp
authors.initials: MP
authors.lastname: Henrichs
authors.forename: Jendrik
authors.initials: J
authors.lastname: Hardes
mesh_terms: D017541:Aneurysm, False / Q000150:complications / Q000175:diagnosis*; D000792:Angiography; D001706:Biopsy; D005096:Exostoses / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006406:Hematoma; D006801:Humans; D007717:Knee / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D009765:Obesity; D015831:Osteochondroma / Q000150:complications* / Q000175:diagnosis*; D010146:Pain / Q000175:diagnosis*; D055815:Young Adult