Gastric Mucosa-associated Lymphoid Tissue Lymphoma That Relapsed after 11 Years Subsequent to Achieving Complete Remission

A 38-year-old Japanese man was diagnosed with extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue in the stomach (gastric MALT lymphoma). Fluorescence in situ hybridization analysis revealed the absence of t (11;18) (q21;q21) translocation but the presence of extra copies of MALT1, indicating tetrasomy 18. Helicobacter pylori eradication led to complete remission (CR). However, the gastric MALT lymphoma relapsed after 11 years old. This case underscores the need for long-term observation (>10 years) of patients with gastric MALT lymphoma. Further investigation is warranted to elucidate the correlation between trisomy/tetrasomy 18 and the recurrence propensity.