[1064] Histopathological Work-Up and Interpretation of Sentinel Lymph Nodes Removed for Vulvar Squamous Cell Carcinoma

S Regauer. Medical University Graz, Graz, Austria

Background: Identification / removal of sentinel lymph nodes (SLN) in vulvar squamous cell carcinoma (SCC) aims at the reduction of long-term morbidity from complete lymphadenectomies related to wound healing, inguinal seromas, lymph edema, infections and erysipel. Correct histopathological work-up of SLN is imperative, as patients with inguinal recurrence / disease have a high risk to die from systemic disease. Work-up and interpretation of SLN from vulvar SCC differs from that in other organs, in particular from breast cancer. Our experience with the SLN protocol of 49 patients with vulvar SCC during the last 8 years and the specific differences of this protocol with respect to other organ systems is presented.
Design: Only patients with pT1 or 2 vulvar SCC without clinically enlarged lymph nodes were included. SNL were identified with lymphoscintigraphy (Tc) and blue dye in a same-day procedure following essentially the sentinel lymph nodes protocol of the Groningen International Study on Sentinel lymph node precedure in vulvar cancer (GROINSS). A frozen section was perfomed on all removed SLN. After a negative frozen section, all SLNs were formalin-fixed, sectioned entirely at 325 m intervals for 2 HE-stains and 1 unstained slide for immunohistochemistry per millimeter. In the absence of metastases on HE sections, ALL unstained slides are submitted for immunohistochemistry with antibody to cytokeratin (CK). SCORING IS POSITIVE EVEN WHEN ONLY INDIVIDUAL CK-POSITIVE CELLS ARE IDENTIFIED.
Results: 13 / 49 patients with SCC (34 pT2, 10 pT1b, 5 pT1a) had obvious metastases on HE stains. After CK-staining, the SLN of 28/35 patients remained negative and 4 patients revealed micro-metastases in the SLN . 4 patients showed only individual single CK-positive cells & debris in their SLN. In 1 of these 4 patients, the individual single cells were corectly identified but interpreted as negative in analogy to breast cancer SLN interpretation. This patient developed conglomerate metastases within 9 months. None of the patients with pT1a SCC had a metastasis. Except for 1 patient with a pT1b SCC, all metastases were from pT2 vulvar SCC. All patients with single cells and cytokeratin positive cell elements in the SLN had a well to moderately differentiated keratinizing SCC arsing in the background of lichen sclerosus.
Conclusions: With a careful and complete histopathological work-up of all removed SLN and a correct interpretation of the staining results, SLN dissection for vulvar SCC can be considered a safe procedure for patients with vulvar SCC.
Category: Gynecologic

Monday, March 9, 2009 1:00 PM

Poster Session II # 128, Monday Afternoon