Primary breast mucosa-associated lymphoid tissue (MALT) lymphoma with high-grade transformation evidenced by prominent lymphoepithelial lesions.

Primary breast lymphoma, particularly primary mucosa-associated lymphoid tissue (MALT) lymphoma, is a rare disease. We report here a case of a MALT lymphoma of the breast with high-grade transformation. An 84-year-old woman presented with a Pagetoid mass in her right breast.