Intramammary lymph nodes

To determine the prevalence and pathology of intramammary lymph nodes in breast specimens.

All breast specimens examined by a single pathologist over 70 months in a large teaching hospital were studied retrospectively. All the surgical pathology reports were reviewed. Relevant glass slides from cases in which intramammary lymph nodes were identified were also reexamined.

Breast specimens (n = 682) were examined. Seven lymph nodes were found in five patients. The specimens comprised 533 biopsy specimens, 29 segmental resections, 22 reduction mammoplasties, 77 modified radical mastectomies and 20 gynecomastia mastectomies. No clinically relevant microscopical abnormalities were found in four lymph nodes and slight sinus histiocytosis was seen in two nodes. One node contained metastatic adenocarcinoma and benign glandular epithelial inclusions.

Although rare, intramammary lymph nodes may be detected by careful gross examination of breast specimens even in the absence of clinical identification. They can occur in any quadrant of the breast and can display a variety of pathological conditions. Pathologists should be alert to the existence and potential importance of these lymph nodes.