title: Misdiagnosis of knee venous malformation as juvenile idiopathic arthritis.
abstract: BACKGROUND
  Initial clinical presentation of knee venous malformation can mimic that of juvenile idiopathic arthritis, posing a diagnostic dilemma. In this communication, we discuss the diagnostic challenges encountered in children with venous malformation of the knee who were misdiagnosed as having juvenile idiopathic arthritis. We highlight the clinical and imaging differences between these 2 disorders with the goal of preventing these diagnostic pitfalls in the future.
  
  
  METHODS
  We conducted a comprehensive search of our databases at Children's Hospital Boston over the last 11 years (1999 to 2009) for patients with venous malformation of the knee who were initially given the diagnosis of juvenile idiopathic arthritis. A retrospective review of the medical records, photographs, and imaging studies was performed.
  
  
  RESULTS
  Of the 56 patients found to have venous malformations of the knee, 6 patients (0 to 13 y, 4 females) were initially misdiagnosed as juvenile idiopathic arthritis and managed as such. Five of the 6 patients received nonsteroidal anti-inflammatory drugs. Of these 5, corticosteroids were also administered in 2 patients, and 1 also received methotrexate. One patient was treated conservatively.
  
  
  CONCLUSIONS
  Venous malformation of the knee can present as a clinical mimicker of juvenile idiopathic arthritis. Familiarity with the clinical presentation and imaging findings of these 2 disorders should minimize misdiagnosis of knee venous malformation as juvenile idiopathic arthritis and thus avoid inappropriate or delayed therapy.
  
  
  METHODS
  Types of Studies: Diagnostic Studies-Investigating a Diagnostic Test, Level III.
authors.affiliation: Department of Radiology, Children's Hospital Boston, Boston, MA 02115, USA.
authors.forename: Andy
authors.initials: A
authors.lastname: Tsai
authors.forename: Gulraiz
authors.initials: G
authors.lastname: Chaudry
authors.forename: Samantha
authors.initials: S
authors.lastname: Spencer
authors.forename: James R
authors.initials: JR
authors.lastname: Kasser
authors.forename: Ahmad I
authors.initials: AI
authors.lastname: Alomari
mesh_terms: D001171:Arthritis, Juvenile / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007719:Knee Joint / Q000098:blood supply / Q000473:pathology*; D008297:Male; D012189:Retrospective Studies; D054079:Vascular Malformations / Q000175:diagnosis* / Q000473:pathology