High-grade Hepatic Mucosa-associated Lymphoid Tissue (MALT) Lymphoma Probably Transformed from the Low-grade Gastric MALT Lymphoma

The Mucosa-associated lymphoid tissue (MALT) lymphoma, which was first described in 1983, is known to be caused by chronic Helicobacter pylori (HP) infection, which triggers lymphoid infiltration and formation of organized lymphoid tissue. In approximately two thirds of cases of MALT, the lymphoma has been observed to regress after treatment of H. pylori infection; this provides strong evidence of a causative role of HP in the etiology of MALT. We report a case of a 67-year-old female patient with a high-grade MALT lymphoma of the liver; this occurred six years after complete remission of a low-grade gastric MALT lymphoma and after complete eradication of H. pylori. there was no recurrence of the previous low-grade gastric MALT lymphoma. Based on radiological and pathologic findings, the high-grade MALT was considered to result from transformation of the low-grade gastric MALT lymphoma.