"On CT and MRI, the primary imaging features are enlargement of the lacrimal gland and/or extraocular muscle(s) 3. Involvement is bilateral in a majority 1,3. The muscle most often affected and most prominently enlarged is the lateral rectus muscle 3. The anterior tendon is spared in the vast majority 3."
"Patients usually present with either painless periorbital/eyelid swelling or proptosis, with or without diplopia 1-3. Pain affects a small fraction 3."
"Within the orbit, IgG4-related disease can involve one or multiple tissue compartments, including the lacrimal gland (dacryoadenitis), extraocular muscles (orbital myositis), orbital fat, sclera, and cranial nerve branches. The most common sites are the lacrimal gland and extraocular muscles, which are affected in the majority of patients with this diagnosis 1-3."