Figure 1.

Primary tumor and sentinel lymph node (SLN). The SLN is defined as one or more lymph nodes that first receive lymphatic drainage from the site of the primary tumor. For intraoperative lymphatic mapping and sentinel lymphadenectomy, blue dye and/or radioisotope‐labeled colloid are injected intradermally (or submucosally) around the primary tumor site before surgery. Subsequently, the tracers pass through the afferent lymphatics, and blue‐stained or radioactive nodes are regarded as the SLN.