||Andrew G. Lee, MD, Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, TX; Professor of Ophthalmology, Weill Cornell Medicine; Jason Zehden, Baylor College of Medicine Class of 2021
||So, we're talking today about orbital pseudotumor. The preferred term is actually idiopathic orbital inflammatory syndrome, but it still goes by the old name pseudotumor. And, orbital ; inflammatory disease is just like inflammation anywhere else, we're going to have dolor, calor, rubor, and tumor. It's going be red, hot, swollen, painful. The tumor in the orbit doesn't have to be a tumor, it can be a pseudotumor and that means proptosis. So, a patient with idiopathic orbital inflammatory syndrome normally presents with symptoms of redness, pain, edema, proptosis, double vision, or loss of vision from an optic neuropathy. These signs are going to be orbital and that means we have to do a Hertel exophthalmometer to look for proptosis. And, the rest of the eye exam is to look for the diplopia, ophthalmoplegia, document the lid findings, and the disc appearance. If we have localization to the orbit, we're going to image the orbit. Normally that means CT or MRI. And, what we're looking for is inflammation in the orbit. Depending on which structure in the orbit is involved, that's how we characterize and define and classify the orbital inflammatory pseudotumor. So, if it's in the lacrimal gland, it's dacryoadenitis, if it's in the muscles it's myositis, if it's in the optic nerve sheath it's optic perineuritis. So, depending on where the inflammation is, the enhancement and enlargement will be seen in that particular structure in the orbit. If it's involving multiple structures or it's in the fat and it's just a big blob then we just call it idiopathic orbital inflammatory pseudotumor. You need to know however because idiopathic is a diagnosis of exclusion that we have to consider the mimics. It doesn't have to be idiopathic, it could be inflammation from another cause. The most common things are immunoglobulin G (IgG) number four and sarcoidosis. But the mimics and the usual suspects have to be considered including the ANCA related vasculitides like granulomatosis with polyangiitis (GPA) since all the ANCA related vasculitides could mimic orbital inflammatory pseudotumor. Churg-Strauss, now called eosinophilic granulomatosis with polyangiitis, lupus, polyarteritis nodosa, and polycondritis. All of these inflammatory disorders elsewhere could produce inflammatory disease in your orbit. So normally we would treat the patients with a short course of steroids first and if they recur then we would biopsy it, but we also would probably consider working these patients up for the non-idiopathic orbital inflammatory syndromes. So, when you're thinking about orbital inflammatory disease, think dolor, calor, rubor, tumor, or red, hot, swollen in the orbit. The tumor in the orbit is going to cause proptosis, but the tumor in this case is from a pseudotumor. We're going to do a CT and an MRI to see where the enlargement and enhancement is. We're going to treat the patient empirically with steroids. And, we're going to work up the patient for the non-idiopathic causes of inflammation, inflammation elsewhere, before we call it idiopathic.