Mucosa-associated lymphoid tissue lymphoma in thymus: a SEER analysis

The present study explores an extremely rare disease, thymic mucosa-associated lymphoid tissue (MALT) lymphoma, for its characteristics and prognostic factors by analyzing the Surveillance, Epidemiology, and End Results (SEER) database.From 2000 to 2018, cases with a diagnosed thymic MALT lymphoma were extracted. Clinical characteristics, treatments, and survival patterns of these cases were analyzed.Thymic MALT lymphoma (n = 26) accounted for 0.09% of all MALT lymphomas. With a sex ratio of 0.53 (male/female), 68% white population was affected. Most cases were diagnosed with Ann Arbor stage I (50%), yet advanced-stage did not show worse prognosis (p = 0.236). Different treatment protocols did not influence the overall prognosis (p > 0.99). The 5- and 10- year overall survival rates were 83.1% and 78.2%, respectively. Older than 70 years may be an independent risk factor for overall survival (HR = 7.166 [95% CI 1.173-43.756], p = 0.033).Thymic MALT lymphoma is a highly rare disease with a favorable prognosis. Ann Arbor staging might not be appropriate to classify severity of this disease or its treatment. Older people may have worse survival. A standardized treatment mode needs to be established, and surgery could remain as the mainstay.