Time to redefine the intramammary lymph node as a separate entity?

The lymphatic drainage for the majority of primary breast tumors is to the axillary lymph nodes (ALNs). Some, however, drain to the so-called extra-axillary basins, namely the internal mammary, supra- and infraclavicular regions. Another potential drainage route includes the intramammary lymph nodes (IMLNs). Current guidance suggests IMLNs should be considered as part of the axillary group, potentially affecting axillary management. However, due to evolution in imaging and advancement in technology, IMLNs may now be distinguished more accurately pre-operatively. There are currently no published guidelines for the management of IMLNs in the United Kingdom. The authors suggest that it is time to reclassify IMLNs as a separate focus of cancer and treat it as a separate entity. Clin. Anat. 31:684-687, 2018.