Is Intraoperative Evaluation of Sentinel Lymph Nodes for Metastatic Melanoma by Imprint Cytology Useful?
Intraoperative evaluation is an addition to the sentinel lymph node (SLN) procedure that allows for a single procedure with regional lymph node dissection to be performed when the SLN is positive. Patients with malignant melanoma undergoing SLN biopsy were examined using a double indicator technique. Four hundred sixty eight SLNs were excised from 172 patients (2.7 SLN/patient). On a per-patient basis, metastases were identified in 37 patients (21%), on permanent section evaluation. Of these, 13 patients were detected by intraoperative imprint cytology (IIC) (sensitivity, 35%). Negative predictive value was 86%. No false positives were identified (specificity, 100%). Positive predictive value was 100%. Overall accuracy of intraoperative evaluation was 78%. The sensitivity for detecting macrometastases (>2 mm) was significantly better than for detecting micrometastases (≤2 mm), 70% versus 21%, respectively (P<0.01). IIC is a viable alternative to frozen sectioning when intraoperative evaluation is desired. IIC evaluation of SLNs in malignant melanoma makes a single operative procedure possible for a significant proportion of patients with regional nodal metastases.