In this case, the inflammatory changes involve the extra-ocular muscles, intra and extra-conal planes as well as the pachymeninges, with the typical dark signal on T2 WI, which raised the possibility of inflammatory pseudotumor.
Biopsy confirmed inflammatory pseudotumor.
CT scan of the chest, abdomen and pelvis were unremarkable. No evidence of sarcoid or Wegener.
Orbital pseudotumor is an idiopathic autoimmune inflammatory condition that most commonly involves the extraocular muscles. Less commonly there is inflammatory changes involving the uvea, sclera, lacrimal gland, and retrobulbar soft tissue.
The condition has been associated with other inflammatory and autoimmune conditions:
- Cavernous sinus
- Dura mater
- Extraocular muscles
- Fibrosing mediastinitis
- Granulomatosis with polyangiitis
- Idiopathic orbital inflammation
- IgG4-related disease
- IgG4-related orbital disease
- Lacrimal gland
- Polyarteritis nodosa
- Rheumatoid arthritis
- Riedel thyroiditis
- Sclerosing cholangitis
- Systemic lupus erythematosus