LAUSR

An elderly man had noticed swelling of his right eye for some time before the exophthalmos rapidly progressed (Picture A, above). He also had conjunctival congestion. A right orbital tumor was observed with a high-intensity signal on diffusion-weighted magnetic resonance imaging and uniform enhancement on T1-weighted images (Picture B). The right extraocular muscle was being compressed by the orbital tumor. Serum levels of thyroid-related antibodies and plasma immunoglobulin G4 were normal. Fluorodeoxyglucosepositron emission tomography / computed tomography showed a significant uptake of the tracer in the ophthalmic tumor and an accompanying nasal mass (Picture C), for which a diagnosis of diffuse large B-cell lymphoma was confirmed by a nasal biopsy specimen. The exophthalmos and conjunctival congestion improved immediately after the initial course of chemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (Picture A, below). This case suggests that malignant lymphoma should be taken into consideration as a differential diagnosis in cases of unilateral exophthalmos. Immediate therapeutic intervention is required to prevent irreversible diplopia and visual field defects (1, 2).