Idiopathic Orbital Inflammation

Abstract

Idiopathic orbital inflammation (IOI), formerly called orbital pseudotumor, is an unusual orbital-specific disorder of unknown origin, characterized by nonspecific orbital inflammation. It can affect any or all of the orbital structures but, most frequently, the lacrimal gland and extraocular muscles. Lacking pathognomic clinical and radiological features, IOI constitutes a diagnostic challenge for it is diagnosed by exclusion. In a clinicoradiologic context suggesting IOI, lesions of the lacrimal gland and orbital fat require biopsy to histologically confirm compatibility with IOI and exclusion of other disorders, where lesions of the extraocular muscle may be diagnosed based on corticosteroid responsiveness. Treatment is tailored to severity and patient morbidity and includes surgical debulking and corticosteroids as first-line therapy, in combination with radiation and immunomodulators as second- and third-line therapy.