Sentinel lymph node detection and microstaging in vulvar carcinoma.

OBJECTIVE: To determine the efficacy of using complementary techniques for detecting sentinel lymph nodes (SLNs) in vulvar carcinoma and to evaluate the utility of microstaging techniques. STUDY DESIGN: Patients with invasive vulvar carcinoma underwent sentinel lymph node detection (SLND) using preoperative lymphoscintigraphy, intraoperative isosulfan blue dye injection and an intraoperative hand-held gamma-detecting probe. Eleven patients were included and a total of 16 groins evaluated. Sentinel nodes identified were excised, bisected and examined in surgical pathology using hematoxylin and eosin (H&E) staining. Pathologically negative SLNs were subjected to additional microstaging via serial sectioning and immunohistochemical staining for cytokeratin. Surgical management of the vulvar cancer and extent of inguinal-femoral lymphadenectomy were individualized based on clinicopathologic parameters, including depth of invasion, location of the tumor and patient performance status. RESULTS: Lymphoscintigraphy, dye and gamma-detector methods led to the total detection of 16, 19 and 17 SLNs, respectively. In two cases the isosulfan blue dye assisted in the isolation of an additional sentinel node over that of the gamma probe. Each method individually identified SLNs in 10/11 patients (91%). A total of 19 sentinel nodes were isolated. One SLN (5%) was positive for metastatic disease using H&E staining. Of the 18 negative SLNs, 2 (11%) had micrometastases (< 0.2 mm) upon serial sectioning and immunohistochemical staining. CONCLUSION: Combined-modality mapping enhances detection of SLNs in vulvar carcinoma. Histologic microstaging improves the detection of micrometastases within SLNs.