title: Synovial hemangioma: imaging features in eight histologically proven cases, review of the literature, and differential diagnosis.
abstract: OBJECTIVE
  This study was undertaken to describe the imaging characteristics of synovial hemangioma, with the goal of improving the disappointing rate (22%) of clinical diagnosis of this condition. A review of the literature and the differential diagnosis of intra-articular lesions, including synovial osteochondromatosis and pigmented villonodular synovitis, are also presented.
  
  
  METHODS
  The subjects of the study were 8 patients (4 males, 4 females; age range: 5-47 years; mean age: 19 years) with histologically confirmed synovial hemangioma involving the knee (n = 7) or wrist (n = 1). We retrospectively examined the imaging studies performed in these patients, including plain radiography (n = 8), magnetic resonance imaging (MRI; n = 4), angiography (n = 3), arthrography (n = 2), and contrast-enhanced computed tomography (CT; n = 2).
  
  
  RESULTS
  Plain radiographs showed a soft tissue density suggesting either joint effusion or a mass in all patients. Phleboliths and bone erosions on plain films in four patients with extra-articular soft tissue involvement pointed to the correct diagnosis. Angiography, showing fine-caliber, smooth-walled vessels, contrast pooling in dilated vascular spaces, and early visualization of venous structures, was diagnostic in two patients. Neither arthrography nor CT yielded specific enough findings. MRI was consistently effective in allowing the correct diagnosis to be made preoperatively, showing an intra-articular or juxta-articular mass of intermediate signal intensity on T1-weighted images and of high signal intensity of T2- or T2*-weighted images with low-signal channels or septa within it. A fluid-fluid level was found in two patients with a cavernous-type lesion.
  
  
  CONCLUSIONS
  Despite the limited nature of this study, it shows clearly that MRI is the procedure of choice whenever an intra-articular vascular lesion such as synovial hemangioma is suspected. Nonetheless, phleboliths and evidence of extra-articular extension of plain radiographs point to angiography as an effective procedure of first resort because it can be combined with embolotherapy.
authors.affiliation: Department of Radiology, University of California, Davis Medical Center, Sacramento 95817, USA.
authors.forename: A
authors.initials: A
authors.lastname: Greenspan
authors.forename: E M
authors.initials: EM
authors.lastname: Azouz
authors.forename: J
authors.initials: J
authors.lastname: Matthews
authors.forename: J C
authors.initials: JC
authors.lastname: Décarie
mesh_terms: D000293:Adolescent; D000328:Adult; D001175:Arthrography; D001862:Bone Resorption / Q000000981:diagnostic imaging; D002137:Calculi / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006391:Hemangioma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D006392:Hemangioma, Cavernous / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018216:Osteochondromatosis / Q000175:diagnosis; D011856:Radiographic Image Enhancement; D012189:Retrospective Studies; D013583:Synovial Membrane / Q000000981:diagnostic imaging / Q000473:pathology*; D013586:Synovitis, Pigmented Villonodular / Q000175:diagnosis; D014057:Tomography, X-Ray Computed; D014652:Vascular Diseases / Q000000981:diagnostic imaging; D014955:Wrist Joint / Q000000981:diagnostic imaging / Q000473:pathology*
chemical_list: D003287:Contrast Media