Pediatric Dermatomyositis

  • Etiology: autoimmune inflammatory myositis with multisystemic features
  • Radiograph: calcification is complication of longstanding or severe disease and is best seen on radiographs
  • MRI: widespread and diffuse / bilateral and often symmetrical STIR / T2 hyperintensity in proximal muscles without atrophy, anterior compartment dominant (vastus lateralis / intermedialis)
  • Clinical: proximal weakness, puritic rash on exposed skin especially extensor surfaces (heliotrope rash)

Radiology Cases of Dermatomyositis

MRI of dermatomyositis
Axial T2 (upper left) and coronal STIR (upper right) MRI without contrast of the pelvis show increased signal intensity in all of the muscles in the pelvis and thighs while the coronal T1 without contrast (lower left) and coronal T1 with contrast (lower right) MRI of the pelvis show enhancement in all of the muscles in the pelvis and thighs.