Primary non-Hodgkin's lymphoma arising in an intramammary lymph node.

Non-Hodgkin's lymphoma (NHL) of the breast may be primary or secondary. Both are rare and there are no morphological criteria to make the differential diagnosis. Benign intramammary lymph nodes are often encountered, but the development of either primary or secondary lymphoma within an intramammary lymph node is extremely rare. We report the case of a 72-year-old woman who presented with a palpable mass in her right breast. A mammography showed a large intramammary lymph node from which a biopsy was taken. On morphological and immunohistochemical examination the tumor fulfilled the criteria of NHL originating in an intramammary lymph node. The patient received chemotherapy which led to the disappearance of the mass. A review of the literature revealed that this is the third reported case of primary NHL originating in an intramammary lymph node.