High grade MALT-lymphoma of the breast.

A 65-year-old woman presented with a rapidly growing breast tumor, initially diagnosed as a carcinoma. Histology showed a breast lymphoma of high grade MALT-type. A lymphoma should always be considered in the differential diagnosis of a breast tumor, because it needs a different work-up and treatment. The subgroup of NHL of Mucosa-Associated-Lymphoid-Tissue origin has different clinical behaviour, as illustrated in this report.