An unusual orbital tumor in an adult: Granuloma annulare

PURPOSE: Granuloma annulare (GA) is a rare clinical entity that does not classically arise from the peri-orbital area in adults. The purpose of this case report is to present a 69-year-old female with GA of the orbit. As well, the pathological and immunohistochemical features of these tumors will be discussed. OBSERVATIONS: One case of GA of the orbit was identified from a tertiary ophthalmology referral centre. Clinical and histopathological features of the case were reviewed. Other cases of GA were also retrieved from the literature and addressed in this report. CONCLUSION AND IMPORTANCE: Granuloma annulare is a rare orbital lesion in adults. It is known to typically arise on the hands and feet of children. This lesion must be distinguished from necrobiotic xanthogranuloma (NXG), which is a progressive peri-orbital dermatosis seen in middle age men and women. GA is thought to be a benign, often self-resolving condition, whereas NXG tends to be linked to other systemic conditions and may have a poorer prognosis. Differentiating this rare orbital tumor from necrobitotic xanthogranuloma (NXG) is essential, as both a systemic work-up and follow-up must be appropriately arranged. A comprehensive description of pathognomonic microscopic features of GA and NXG is reviewed to achieve the correct diagnosis.