The clinical relevance of sentinel lymph nodes identified with radiolymphoscintigraphy.

Background: The purpose of this case report is to illustrate the utility of radio-guided mapping of sentinel lymph nodes (SLN's) as demonstrated by the technique's successful identification of nodes containing metastatic disease that would have been left behind if only the visual-oriented vital blue dye mapping technique had been used.

Method: The patient underwent preoperative lymphoscintigraphy and intra-operative lymphatic mapping using vital blue dye and radiolymphoscintigraphy using the Neoprobe (handheld gamma probe). Nodes which were blue and/or "hot" (i.e., radioactive counts were three times the background count) were considered SLN's.

Results: Four SLN's were harvested, all of which were "hot" but only one of which was both "hot" and blue. Pathology revealed that the two SLN's positive for metastatic disease were not blue.

Conclusion: While the blue dye lymphatic mapping technique provides the surgeon with a visual road map in the identification of SLN's, the Neoprobe increases the success rate of localization when compared to vital blue dye mapping due to the reliable migration of radiocolloid to the SLN's in the regional basin. Radiolymphoscintigraphy also increases the accuracy and efficiency of the SLN harvest by providing a directed dissection to the level of the nodes in the basin. The Neoprobe increases the yield of SLN's, some of which are clinically relevant since they contain metastatic disease.