To report a case of lacrimal gland mucosa-associated lymphoid tissue (MALT) lymphoma in a patient with primary Sjögren's syndrome and Behcet's disease.

A 49-year-old female patient with primary Sjögren's syndrome and Behcet's disease presented with a one-year history of painless upper and lower eyelid swelling in her right eye. Lacrimal gland incisional biopsy was performed, and the patient was diagnosed with malignant lymphoma (extranodal marginal zone B cell lymphoma of MALT). No distant metastases were detected on whole-body computed tomography or positron emission tomography, and the patient was treated with Rituximab, Cyclophosphamide, Vincristine, Prednisone (R-CVP) regimen chemotherapy. After 8 consecutive chemotherapy cycles, her eyelids appeared normal externally, and partial regression was found radiologically.

The possibility of MALT lymphoma should be considered as a differential diagnosis if patients with autoimmune diseases such as primary Sjögren's syndrome show eyelid swelling or palpable mass.