Significance of preoperative lymphoscintigraphy and thin-slice computed tomography on sentinel node assessment: metastatic sentinel node in a lateral paramammary lesion out of axillary nodes from breast cancer.

Sentinel node status was evaluated using preoperative lymphoscintigraphy in a 43-year-old woman who presented with an invasive ductal carcinoma in the lower outer quadrant of the right breast. Two strong hot nodules were visualized in the affected axillary basin on an early image, and a faint accumulation of radioactive tracer was lying between the cancer in the right lower outer quadrant and the axillary hot nodules on the lymphoscintigram taken at 90 min. The faint accumulation was considered to represent a small paramammary node on thin-slice computed tomography (CT) and was confirmed by node biopsy to be a sentinel node grossly involved with tumor cells. Immediate axillary dissection and adjuvant chemotherapy was subsequently performed. Careful evaluation using lymphoscintigraphy and thin-slice CT may be associated with increased localization of true sentinel nodes.