LAUSR

PURPOSE To analyse the incidence and characteristics of ocular adnexal mucosa-associated lymphoid tissue lymphoma (OAML) with immunoglobulin G4 (IgG4)-related ophthalmic disease (IgG4-ROD), and to compare with IgG4-negative OAML. METHODS We enrolled 130 patients with pathology-confirmed OAML at a single tertiary medical centre. Patients were divided into IgG4-positive and IgG4-negative groups based on the pathologic criteria for IgG4-ROD. The data were reviewed and compared between the groups. RESULTS IgG4-positive OAML was identified in 5.4% (7/130) of OAML and 13.5% (7/52) of non-conjunctival OAML. IgG4-positive group had a higher incidence of involvement of the lacrimal gland (7/7 vs. 18/123, p = .001), extraocular muscles (3/7 vs. 10/123, p = .022) and infraorbital nerve (2/7 vs. 0/123, p < .001), and had a lower incidence of involvement of the conjunctiva (0/7 vs. 84/123; p < .001) than IgG4-negative group. IgG4-positive group had higher T and N categories of the American Joint Committee on Cancer classification (T1:T2:T3:T4 ratio of 0:6:0:1 vs. 78:32:8:5, p < .001; and ≥N1 ratio of 2/7 vs. 7/123, p = .021). There were no differences in the response rate to initial treatment (5/6 vs. 39/41, p = .343) or the relapse rate (1/6 vs. 5/41, p = 1.000) between the groups. CONCLUSION IgG4-positive OAML showed clinical features similar to IgG4-ROD, such as predominant disease involvement of the lacrimal gland, extraocular muscles, infraorbital nerve and lymph nodes, but not the conjunctiva. However, treatment outcomes were favourable with or without background IgG4-ROD. Physicians should be aware that IgG4-ROD might undergo a malignant transformation and that thorough treatment and surveillance of IgG4-ROD are important.