What should be included in differential diagnosis?
orbital pseudotumour, orbital arteriovenous malformation, orbital sarcoidosis, Orbital lymphoma, orbital metastases, orbital amyloidosis (rare), Erdheim Chester disease.
What is the popular mnemonic to remember the order in which extraocular muscles are involved in this condition?
I'M SLOW: I: inferior rectus M: medial rectus S: superior rectus L: lateral rectus O: obliques
Bilateral proptosis and enlargement of multiple rectus muscles. Crowding, but not compression of the optic nerve, at the orbital apex.