212 IgG4-Positive Plasma Cells in Adult Orbital Xanthogranulomatous Disease Without IgG4-Related Disease: A Series of Two Cases. (11th January 2018)

• Record Type: Journal Article
• Authors: Brem, Candice; Tang, Bang; Silverman, Jan; Bunker, Mark
• Is Part Of: American journal of clinical pathology. Volume 149(2018)Supplement 1
• Page Start: S90
• Page End: S91
• Publication Date: 2018-01-11
• Subjects: Diagnosis, Laboratory -- Periodicals; Pathology -- Periodicals; 616.07
• DOI: 10.1093/ajcp/aqx123.211
• Languages: English
• ISSNs: 0002-9173

Abstract

Abstract: Adult orbital xanthogranulomatous disease (AOXD) is a heterogeneous umbrella category encompassing four relatively rare syndromes: adult-onset xanthogranuloma (AOX), adult-onset asthma and periocular xanthogranuloma (AAPOX), necrobiotic xanthogranuloma, and Erdheim-Chester disease. This group of non-Langerhans cell histiocytic disorders, though differing significantly in clinical presentation and symptomatology, is unified by overlapping histopathologic features, which include Touton giant cells, mononucleated foamy histiocytes, fibrosis, and lymphoplasmacytic inflammation. Recently, though various articles have described certain types of AOXD to be associated with IgG4-related disease (IgG4-RD), definitive evidence of a substantial connection is lacking. A case series by Verdijk et al has demonstrated that 50% of AOXD cases contain increased IgG4-positive plasma cells, while less than 25% of these cases develop IgG4-RD. We present two cases of AOXD of the lacrimal gland, specifically cases of AOX and AAPOX, which demonstrate increased numbers of plasma cells (>100/hpf and >50/hpf) and increased IgG4/IgG ratios exceeding 40% (61.3% and 57.3%). The AOX case, as per the Boston criteria, could be considered "histologically highly suggestive of IgG4-RD" as it demonstrates fibrosis with an increased plasma cell infiltrate (>100/hpf) and IgG4:IgG ratio >40%. However, the AAPOX case, though demonstrating similar histology and IgG4:IgG ratio, can at best be "probable histological features of IgG4-RD" due to a subpar plasma cell increase (<100/hpf). Upon further clinical evaluation, both patients are currently negative for the stigmata of systemic IgG4-RD. We present these cases to increase awareness of AOXD and further support that increased IgG4-positive plasma cells in AOXD may be a hallmark of a localized immune reaction without definitive association with an IgG4-RD.