INTERNAL MAMMARY LYMPHADENOPATHY

• Metastases to the internal mammary nodes usually occur after a tumor has metastasized to the axilla
  • Nodal staging is considered N3b (stage IIIC disease)
• Isolated metastases to the internal mammary nodes occur in 1%–5% of breast cancers and usually come from deep or medial lesions
  • In the absence of axillary metastases, involvement of the internal mammary nodes constitutes N2 disease
• No survival benefit to surgical treatment of internal mammary node metastases, and because of the morbidity, dissection of the nodes is not usually performed
• Radiation treatment planning may be altered if metastases of the internal mammary nodes are identified

Related Radiology Article:  Ecanow JS, Abe H, Newstead GM, Ecanow DB, Jeske JM. Axillary staging of breast cancer: what the radiologist should know. Radiographics. 2013 Oct;33(6):1589-612.