Clinical implications of contralateral axillary sentinel lymph nodes.

Extra-axillary sentinel lymph nodes can only be detected if radioactive tracer is used and pre-operative scans are carried out. The presence of metastatic sentinel lymph nodes in most extra-axillary sites will upstage patients if the ipsilateral axillary sentinel lymph node is normal. Paradoxically, the presence of metastatic sentinel lymph nodes in the contralateral axilla has the potential to prevent upstaging to stage IV, but only if detected as a sentinel node at the initial surgery rather than as a systemic recurrence at some later time. We describe a case of bilateral axillary sentinel lymph nodes detected by pre-operative lymphoscintigraphy in a patient with a medial quadrant breast cancer and discuss the possible implications of such a finding.