Processing of sentinel lymph nodes for detection of metastatic melanoma

Within the last years, evaluation of sentinel lymph nodes (SLN) has become the most popular method of early staging of several malignancies, including breast carcinoma and melanoma. Because SLN are reportedly the lymph nodes most likely to contain metastatic deposits, identification of such nodes allows pathologists to examine the tissue in a much more intense manner than with the usual lymphadenectomy specimens containing multiple lymph nodes. However, there is not a universally accepted standard protocol for pathologic processing of the SLN. Initially, the most popular protocols called for bisection of the SLN and examination of serial sections, with or without routinely performed immunohistochemistry. Lately, other protocols have been proposed to try to simplify the histologic analysis while providing at least equivalent results. Here we review the different protocols used for the evaluation of SLN and describe the protocol currently in use at M. D. Anderson Cancer Center (Houston, TX).