Invasive breast cancer is the most common malignancy in women. Its most common site of
metastasis is represented by the lymph nodes of axilla, and the sentinel lymph node (SLN) is
the first station of nodal metastasis. Axillary SLN biopsy accurately predicts axillary lymph
node status and has been accepted as standard of care for nodal staging in breast cancer.
To date, the morphologic aspects of SLN metastasis have not been considered by the
oncologic staging system. Extranodal extension (ENE) of nodal metastasis, defined as …