<unk><unk><unk>  (IOI)<unk> , refers to a marginated mass-like enhancing soft tissue involving any area of the orbit. It is the most common painful<unk>  mass in the adult population, and is associated with proptosis, cranial nerve palsy (Tolosa–Hunt syndrome), uveitis, and retinal detachment.<unk><unk><unk>  syndrome, also known as<unk>  pseudotumor, was first described by Gleason in 1903 and by Busse and Hochhmein. It was then characterized as a distinct entity in 1905 by Birch-Hirschfeld. It is a benign, nongranulomatous<unk><unk>  process characterized by extraocular<unk>  and adnexal inflammation with no known local or systemic cause. Its diagnosis is of exclusion once neoplasm, primary infection and systemic disorders have been ruled-out. Once diagnosed, it is characterized by its chronicity, anatomic location or histologic subtype.<unk><unk>  inflammation has a varied clinical presentation depending on the involved tissue. It can range from a diffuse<unk>  process to a more localized inflammation of muscle, lacrimal gland or<unk>  fat. Its former name,<unk>  pseudotumor, is derived due to resemblance to a neoplasm. However, histologically it is characterized by inflammation. Although a benign condition, it may present with an aggressive clinical course with severe vision loss and oculomotor dysfunction.
Idiopathic orbital inflammatory disease
Orbital lymphoma
Orbital cellulitis
Neurotrophic keratitis
Ocular ischemic syndrome
Phacolytic glaucoma
Acute hemorrhagic conjunctivitis
Intraocular lymphoma