Nearly a quarter of orbital lymphoproliferative disorders IgG4-related

This retrospective study found that nearly a quarter of orbital lymphoproliferative disorders in Japan are related to immunoglobulin(Ig)G4.

This study included 1,014 patients with orbital lymphoproliferative disorders from 18 institutes in Japan. They all had pathologically diagnosed lymphoproliferative disorders with surgical samples of ocular adnexal tissue. Patients with conjunctival lesions and intraocular lymphoma were excluded.

The authors found that 404 (39.8 percent) had extranodal mucosa-associated lymphoid tissue (MALT) lymphoma, 156 (15.4 percent) had other malignant lymphomas, 191 (18.8 percent) had non-IgG4 orbital inflammation, 219 (21.6 percent) had IgG4-related orbital inflammation and 44 (4.3 percent) had IgG4-positive MALT lymphoma.

The median age of the IgG4-related orbital inflammation group was 62 years, which is significantly lower than that of the MALT lymphoma group (median 66 years) and higher than that of the non-IgG4 orbital inflammation group (median 57 years). The male/female ratio was 105/114 in the IgG4-related orbital inflammation group.

The authors note that the age differences between IgG4-related orbital inflammation and IgG4-positive MALT lymphoma may support the idea that MALT lymphoma arises from pre-existing IgG4-related orbital inflammation. However, they remain uncertain about why the non-IgG4 orbital inflammation group in the study was younger than the IgG4-related orbital inflammation group, but one explanation may be that the former included young patients with orbital lymphocyte infiltrative lesions.

They conclude that further studies are required to evaluate the incidence of each tissue involved in IgG4-related ophthalmic disease.