AB1075 IDIOPATHIC ORBITAL PSEUDOTUMOUR: A CASE SERIES AND LITERATURE REVIEW

Background Idiopathic orbital pseudotumour (IOP), also known as idiopathic orbital inflammatory syndrome is a benign, non-infective, inflammatory condition of the orbit without identifiable local or systemic causes. After Grave’s disease and lymphoproliferative disorders, orbital pseudotumor is the 3rd most common ophthalmologic disease of the orbit and account for approximately 8-11% of all the orbital tumors.Pathogenesis of orbital pseudotumor remains elusive but several lines of evidence point to immune-mediated processes as the likely underlying ocular mechanism. The etiology of orbital pseudotumor is unknown, but infection, autoimmune disorder, and aberrant wound healings have been put forward as possibilities. The ocular manifestations of orbital pseudotumor may include periorbital edema, erythema, proptosis, ptosis, diplopia and pain with eye movements. Objectives Describe clinical and demographic characteristics, most frequent diagnoses, immunological serology and treatments in patients with Orbital Pseudotumor. Methods We performed a retrospective cohort study of adult and pediatric patients with orbital pseudotumor diagnosis referred to the Department of Rheumatology of the Fray Antonio Alcalde Civil Hospital in Guadalajara Jalisco, Mexico, from 2012-2018. We collected data that included demographic data of the patient, symptoms, laboratory data that included antibodies, management plans and results. Results A total of 20 patients diagnosed with orbital pseudotumor, with a mean age of 42±18.5 years, 3 pediatric patients and 65% women. Clinical manifestations were: 90% unilateral, 90% lacrimal gland involvement, 75% ptosis/proptosis, 40% conjunctival hyperemia, 35% ocular pain, 20% decreased visual acuity, 15% headache and no optic nerve involvement. The findings were similar between adults and children. The most common diagnoses were: 40% idiopathic, 10% orbital cellulitis, 10% granulomatosis with polyangiitis and 5% each of the following: systemic lupus erythematosus, Sjogren’s syndrome, dacryoadenitis and myositis due to IgG4, Kimura’s disease, Mikulicz, meningioma and cavernous sinus aneurysm. All patients underwent excisional biopsy, and the histopathological report showed the following findings: 40% non-specific chronic inflammation, 30% non-specific chronic dacryoadenitis, 5% granulomatous inflammation/vasculitis, 10% chronic sclerosing inflammation-IgG4 and 15% others. Only 9 of the 20 patients underwent immunological serology, finding positivity in:15% for c-ANCA, 10% PR3, 5% p-ANCA, 10% MPO, 5% ANAs and 10% elevated blood levels of IgG4. Regarding treatment, 100% received glucocorticoids, and received immunomodulatory therapy: 20% received azathioprine, 5% mycophenolate mofetil, 20% methotrexate, 15% cyclophosphamide IV, 15% rituximab and 25% received no other medication. Conclusion The orbital pseudotumor might be the first manifestation of an autoimmune or autoinflammatory disease, the early and correct diagnosis is necessary to avoid permanent sequelae. References [1] Yuen SJ, et al. Idiopathic orbital Inflamation: Ocular mechanism and clinicopathology. Ophthalmol Clin North Am 2002;15:121-6. [2] Grouteau E, et al. Acute orbital myositis and idiopathic inflammatory pseudotumor in children: cases. Arch Pediatr 1998;5:153-158. [3] Chaudhry IA, et al. Orbital pseudotumor: Distinct diagnostic features and management. Middle East Afr J Ophthalmol 2008;15:17-27 Disclosure of Interests None declared