Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) of the thymus is reported to have characteristic features that distinguish it from MALT lymphoma of other organs; it is proposed to be a distinct clinicopathological subgroup of MALT lymphoma. We herein present a case of thymic MALT lymphoma accompanied by Sjögren's syndrome, involving the first report of a thymic MALT lymphoma patient carrying a chromosomal abnormality of 8q24. No c-myc gene translocation or c-Myc protein overexpression was observed, suggesting that c-myc was not involved in lymphomagenesis or progression. Although we did not examine the mechanisms by which the lymphoma developed, this chromosomal structural change in 8q24 may be associated with the pathogenesis in our case.