Bilateral orbital masses caused by IgG4-expressing MALT lymphoma in the right side and IgG4-related ophthalmic disease in the left side: A case report

A 60-year-old Japanese man developed a protruding right eye. He underwent a magnetic resonance imaging (MRI) scan, which revealed a right orbital mass. The serum immunoglobulin G4 (IgG4) level was elevated and IgG4+ plasma cells were observed in biopsy specimens of the mass. The result of biopsy and Southern blot analysis revealed that the mass was caused by IgG4+ extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). He received a total of 36 Gy of radiation therapy, and the mass disappeared. Five years later, he developed a protruding left eye. The MRI scan at that time revealed a left orbital mass. Biopsy revealed findings of IgG4–related disease (IgG4-RD) in the left orbital mass, but no findings of MALT lymphoma. He has been followed up without glucocorticoid treatment. Here, we report a patient who developed IgG4+ MALT lymphoma in the right orbital mass and IgG4–related ophthalmic disease (IgG4-ROD) in the left orbital mass. Because the treatment strategy for IgG4-ROD and malignant lymphoma is completely different, we emphasize the need for biopsy.