Pathologic examination of the sentinel lymph node

One of the most important prognostic indicators in patients with malignant melanoma is lymph node status. While the five-year survival of stage I and II patients (without clinical adenopathy) is approximately 80 percent, this drops to 36-50 percent in patients with clinical or microscopic lymph node involvement. Other factors within lymph node specimens which affect disease-free and overall survival are the number of positive nodes (1 vs. 1-3 vs. 4 or greater) and the presence of extracapsular extension. Recently, the technique of sentinel lymphadenectomy has been developed to facilitate detection of metastatic disease in regional lymph nodes. Successful completion of this procedure requires a specialized but multidisciplinary approach, utilizing the surgeon, oncologist, nuclear radiologist, and pathologist. The pathologist's role is pivotal in this process, because identification of melanoma metastasis in the sentinel lymph node(s) is not only an important prognostic indicator but also dictates whether the patient will receive further surgery and adjuvant chemotherapy. Therefore, the goal of the pathologist in examining the sentinel lymph node is to maximize identification of nodal metastases of malignant melanoma. This is accomplished by following a standard protocol which fully utilizes all tissue submitted in concert with commonly available immunohistochemical techniques.