An adult xanthogranulomatous disease of the orbit (AXDO) is a subset of non-Langerhans cell histiocytosis. IgG4-related disease (IgG4-RD) is a fibroinflammatory condition affecting multiple organs. The authors reported a case of 47-year-old woman of adult-onset xanthogranuloma (AOX) associated with IgG4-related ophthalmic disease (IgG4-ROD). She had yellow plaques with swelling of both periorbital areas for many years. Histopathological findings showed foamy histiocytes in the dermis with Touton giant cells along with inflammatory infiltrate of lymphocytes, plasma cells, and histiocytes with prominent germinal centers which were consistent with AOX. There were areas of increased fibrosis along with increased number of IgG4+ plasma cells and elevated serum IgG4 level which fulfill criteria of IgG4-RD diagnosis. There was no evidence of IgG4-RD in other organs. She was prescribed oral methotrexate with resulted in minimal improvement. Diagnosis of IgG4-RD in the setting of overlapping with dermatologic diseases is crucial because systemic work up is warranted.

Keywords: IgG4-related disease, IgG4-related ophthalmic disease, periorbital xanthogranuloma, adult-onset xanthogranuloma