Orbital inflammatory disease: Pictorial review and differential diagnosis

Abstract

Orbital inflammatory disease (OID) represents a collection of inflammatory conditions affecting the orbit. OID is a diagnosis of exclusion, with the differential diagnosis including infection, systemic inflammatory conditions, and neoplasms, among other conditions. Inflammatory conditions in OID include dacryoadenitis, myositis, cellulitis, optic perineuritis, periscleritis, orbital apicitis, and a focal mass. Sclerosing orbital inflammation is a rare condition with a chronic, indolent course involving dense fibrosis and lymphocytic infiltrate. Previously thought to be along the spectrum of OID, it is now considered a distinct pathologic entity. Imaging plays an important role in elucidating any underlying etiology behind orbital inflammation and is critical for ruling out other conditions prior to a definitive diagnosis of OID. In this review, we will explore the common sites of involvement by OID and discuss differential diagnosis by site and key imaging findings for each condition.

Keywords: Orbit, Inflammation, Pseudotumor, Orbital inflammatory disease, Nonspecific orbital inflammation, Dacryoadenitis, Myositis, Orbital cellulitis, Optic perineuritis, Orbital apicitis

Core tip: This review provides a pictorial summary of orbital inflammatory disease (OID). It outlines many key aspects of OID on imaging that can be used to distinguish from other pathologic conditions. The review also provides an up-to-date overview of the best approaches to imaging workup when suspecting OID.