Use of the sentinel lymph node to determine metastases of gastrointestinal malignancies: A word of caution

Identifying the sentinel lymph node has been shown to carry prognostic and therapeutic implications in the surgical treatment of solid tumors. Recently, sentinel lymphadenectomy has been described for gastrointestinal malignancies, but its clinical value remains uncertain. We describe the case of a patient with appendiceal carcinoid who underwent a right hemicolectomy 4 months after appendectomy, out of concern over residual local or regional disease. One sentinel lymph node was identified in the colonic mesentery using the blue dye technique. This sentinel node and 35 others were negative for metastases, but one lymph node not identified through blue dye carried evidence for micrometastatic disease on hematoxylin and eosin (HandE) and immunohistochemical chromogranin stains. The case raises some issues about the value and limitations of sentinel lymph node biopsies in gastrointestinal cancer. Aspects related to technique, learning curve, gastrointestinal lymphatic drainage patterns, the impact of prior operations, and the limited therapeutic implications compared to cutaneous or subcutaneous solid malignancies are discussed. We conclude that at this point in time, the information obtained from biopsies of sentinel lymph nodes during the surgical treatment of gastrointestinal cancer should be utilized with due caution.