Pediatric Idiopathic Orbital Inflammation

• Etiology: Idiopathic inflammatory condition that most commonly involves extraocular muscles and less commonly involves the uvea, sclera, lacrimal gland and retrobulbar soft tissue
• Imaging: Enlargement of muscle belly of one or more extraocular muscles typically with involvement of tendinous insertions
• DDX:
  — Orbital lymphoma which presents slowly and is usually bilateral
  — Thyroid associated orbitopathy which spares tendinous insertions of extraocular muscles and is usually painless
  — Orbital cellulitis that has subperiosteal abscess from adjacent cellulitis
  — Orbital rhabdomyosarcoma
• Complications:
• Treatment: Usually resolves rapidly with corticosteroid treatment
• Clinical: Commonly presents with unilateral rapid-onset painful proptosis and diplopia

Radiology Cases of Idiopathic Orbital Inflammation