Sentinel node dissection and ultrastaging in squamous cell cancer of the vulva

The aim of this study was to evaluate the findings when pathologic ultrastaging techniques are applied in conjunction with sentinel node dissection in patients with vulvar cancer.

Patients with squamous cell cancer of the vulva underwent intraoperative lymphoscintigraphy following intradermal injection of 99mTc-labeled sulfur colloid at the site of the primary tumor. Isosulfan blue dye was also injected at the tumor site to facilitate identification of the sentinel node in the groin. Following removal, the sentinel node was then bisected and examined in the standard manner using hematoxylin and eosin staining. Negative nodes were subjected to additional ultrastaging evaluation with serial sectioning and immunohistochemical staining.

Nine patients with 10 primary tumors underwent radical local excision of the primary tumor and sentinel node dissection of the groin. Sentinel nodes were identified and removed in all patients. One node was positive by conventional staining; the remainder were all negative. Of these negative nodes, 2 were found to be positive for micrometastases on serial sectioning and immunohistochemical staining. Therefore 2 of 3 positive nodes were not detected using conventional histologic techniques.

Sentinel node dissection appears to be technically feasible in patients with vulvar cancer. Pathologic ultrastaging combined with sentinel node dissection appears to be highly sensitive for detecting subclinical micrometastases in the regional lymphatics. This technique potentially provides a more accurate assessment with less surgical morbidity than conventional inguinalfemoral lymphadenectomy.