Orbital lymphoma mimicking ophthalmopathy in a patient with Graves'.

The objective of this case report is to present a rare association of a mucosa-associated lymphoid tissue lymphoma masquerading as Graves' orbitopathy in a patient with autoimmune hyperthyroidism, without evidence of Graves' ophthalmopathy. A 66-year-old male patient had pain and swelling of the right eye. Evaluation of serum thyroid hormone revealed low thyrotropin, elevated free thyroxin and antithyroperoxidase antibody levels, confirming the diagnosis of Graves' disease. Computed tomographic scan showed intraorbital muscle asymmetry. Biopsy demonstrated a low-grade, B-cell type non-Hodgkin's lymphoma of the mucosa-associated lymphoid tissue. Treatment included radiotherapy and chemotherapy, with regression of the orbital lesion and medical treatment with methimazole and (131)I. Detailed orbital evaluation should be considered in all patients who present any atypical signs and symptoms of the eyes, to prevent missing important and progressive diagnoses.