Conjunctival Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma Associated With Methotrexate Therapy: A Case of Complete Remission Following Drug Discontinuation

Methotrexate-associated lymphoproliferative disorders (MTX-LPDs) are a distinct clinical entity with potential for spontaneous regression after drug discontinuation. We report the case of a 64-year-old man with rheumatoid arthritis treated with MTX 4 mg twice weekly (8 mg/week) for 11 years, who developed a salmon-pink, lobulated conjunctival mass in the left superior nasal quadrant. Laboratory evaluation showed elevated immunoglobulins, the presence of M-protein, and serum Epstein-Barr virus (EBV)-DNA of 2.18 U/mL. Biopsy confirmed mucosa-associated lymphoid tissue (MALT) lymphoma. MTX was promptly discontinued, and the mass was excised. At 10 months post-withdrawal, the patient achieved complete clinical and biochemical remission, with the disappearance of M-protein and no evidence of recurrence. This case underscores the importance of recognizing MTX-LPD in patients receiving MTX, as prompt drug discontinuation can lead to complete regression without chemotherapy. The conjunctival presentation is rare and broadens the recognized anatomical spectrum of MTX-LPD.