Internal mammary sentinel node metastases in an otherwise lymph-node negative breast cancer patient

A 35 year old woman with biopsy proved breast cancer was submitted for sentinel node (SN) biopsy. Preoperative lymphoscintigraphy displayed both axillary and internal mammary (IM) uptake foci consistent with SNs. Full axillary dissection was completed because of a greater-than 2 cm primary lesion. Two axillary SNs were excised. An IM SN was also excised through the second intercostal space, with the aid of the gamma probe. Fourteen axillary nodes, including SNs, were negative, whereas the IM SN harbored several metastatic implants. Implications for staging, prognosis and further therapy of such IM-only positive sentinel nodes are discussed.