LAUSR

Adult-onset orbital xanthogranulomatous disease (AOXGD) is a rare non-Langerhans (type II) histiocytosis (LCH) involving ocular and orbital tissue and is subclassified into four subtypes including adult-onset xanthogranuloma (AOX), adult-onset asthma and periocular xanthogranuloma (AAPOX), necrobiotic xanthogranuloma (NBX), and Erdheim-Chester disease (ECD) [1]. Although there are apparent clinical and histological differences among subtypes, some share similar histopathological features. The subtype AOX presents as an isolated xanthogranulomatous lesion lacking systemic involvement. Significantly, AOX is occasionally self-limiting and therefore usually does not require aggressive treatment. Other subtypes of AOXGD, such as ECD, can sometimes cause significant morbidity and mortality. Imaging modalities are used to detect the presence of a mass and to delineate the extent of disease; however, to date, no specific radiological findings for AOXGD have been defined. Computed tomography (CT) and magnetic resonance imaging (MRI) were considered by earlier reports to reveal characteristic homogenous infiltrations of the preseptal soft tissue [2, 3]. Although AOXGD is clinically significant, differential preoperative diagnosis is challenging. In this article we report our findings in a patient with confirmed AOX who exhibited interesting imaging fea-