Intraoperative sentinel lymph node analysis in melanoma.

Background: The objective of this retrospective cohort study was to evaluate the sensitivity and specificity of touch preparation cytology (TPC) and frozen section (FS) histology in the intraoperative staging of melanoma.

Methods: The cohort was identified from all patients with clinically node negative melanoma undergoing a SLN biopsy using Technetium and/or blue dye mapping from 1/1998 to 10/2008. TPC and FS analysis was performed utilizing Diff-quick and compared to permanent section interpretation with H&E.

Results: Of 271 patients undergoing SLN biopsy, 163 underwent intraoperative analysis of the sentinel node (125 underwent TPC alone, 15 underwent FS alone, 23 underwent both TPC and FS), and 108 underwent no intraoperative analysis. Thirty-three patients undergoing intraoperative analysis of the SLN were found to have positive nodes (20%) on permanent histology. There were no false positives identified (specificity = 100%). The overall sensitivity for all methods of intraoperative analysis was 61% (20/33). On a per patient basis, the sensitivity was 47% (9/19) for TPC alone, 75% (3/4) for FS alone, and 80% (8/10) for both TPC and FS.

Conclusions: There were no false positives identified suggesting TPC and FS can be used safely to identify the majority of SLN that harbor metastases from melanoma.