[En garde, sentinel node!]

Injection technique and radiocolloid size are two critical parameters that must be carefully selected according to patient presentation and lesion appearance for accurate sentinel node detection in breast cancer. Scintigraphic detection and intraoperative localization are dependent on these parameters. The present clinical case illustrates how much deep intralesional tracer injection bears on our capacity to detect extra-axillary sentinel nodes and how the use of smaller-size radiocolloids may sometimes facilitate sentinel node detection.