[Sentinel lymph node detection and clinical applications]

The sentinel lymph node (SLN) procedure consists of finding the first lymph node encountered by lymphatic vessels draining a tumor. This technique identifies the SLN histological status, which is representative of all the other draining area lymph nodes' status.

SLN identification requires the injection of a lymphatic tracer, which could be either a blue dye or radiolabeled particles, or both. Performing a lymphoscintigraphy, which identifies and quantitates SLNs is a possibility provided by the use of radiolabeled particles before a gamma probe guided search is performed intraoperatively. Finally, a specific histopathological methodology involving serial sections of the entire SLN and immunohistochemistry is also required.

This technique is applicable to melanoma in which the SLN status might be a stronger prognostic factor than Breslow's thickness; to breast cancer in order to avoid full axillary lymph node dissection in patients with small tumors; and potentially to other carcinomas.