Intramammary lymph node metastasis predicts poorer survival in breast cancer patients.

Involvement of an intramammary lymph node with metastatic breast cancer is an uncommon clinical or radiological presentation. Previously reported series of patients are small in number and the clinical advice is unclear. We identified 100 patients on our pathology database with intramammary lymph nodes in association with a primary breast cancer. Ten were identified pre-operatively on breast imaging and 90 were first discovered on pathological assessment of excised breast tissue. Twenty one contained metastasis. Factors that predicted for intramammary node metastasis were increasing age (p=0.017), lymphovascular invasion (p=0.002) and grade of tumour (p=0.012). The presence of metastasis within the intramammary lymph node was associated with a poorer disease free survival (p=0.007) and reduced overall survival (p=0.035). Sixty seven percent of patients with intramammary node metastasis had further axillary metastases. One patient had an intramammary node metastasis but uninvolved axillary sentinel node. She presented 19 months later with an axillary nodal recurrence. The presence of intramammary lymph node metastasis is associated with poorer outcome in breast cancer patients. Pre-operative detection of intramammary lymph node metastasis is helpful to guide breast and axillary surgeries. Intramammary lymph node metastasis predicts strongly for axillary metastatic disease and axillary node clearance is recommended.