Ocular adnexal marginal zone lymphoma arising in a patient with immunoglobulin-G4-related ophthalmic disease: A 4-year delay in diagnosis.

Ocular adnexal marginal zone B cell lymphomas (MZBLs) make up the majority of lymphomas arising from the ocular adnexa. Immunoglobulin-G4 (IgG4)-related disease is a recently proposed entity with several unique clinicopathological features, such as enlargement of affected organs, elevated serum IgG4 level, and infiltration with IgG4-positive plasma cells. Ocular adnexal MZBLs are reported to arise in IgG4-related sclerosing dacryoadenitis, indicating a possible link between the two conditions. Here, we describe a 37-year-old Omani male who presented with right periorbital swelling and proptosis 4 years before presentation. He was diagnosed to have right orbital pseudotumor and exhibited good response to steroid therapy. However, 4 years later, rapid swelling of the right orbital mass was observed. The patient underwent lacrimal gland biopsy. Although the histology was consistent with IgG4-related disease, the infiltrating large atypical lymphoid cells showed that immunoglobulin light-chain restriction and dense lymphoplasmacytic infiltrate involving the soft tissue were seen. Consequently, he was diagnosed with extranodal marginal zone lymphoma with abundant IgG4-positive cells of the right lacrimal gland.