Ultrasound-Guided Inguinal Lymph Node Assessment

All patients underwent preoperative ultrasound examination to assess inguinal lymph nodes and ultrasound-guided fine-needle aspiration cytology or biopsy (FNA) in cases of suspected metastases.
Ultrasound examinations were conducted by two fully-trained gynecologists with more than ten years of experience in the management of vulvar cancer patients (GG and SMF). All ultrasound examinations were performed with MyLab Twice (Esaote, Genova, Italy) machine with 7–12 MHz linear probes.
All the ultrasound parameters of inguinal lymph nodes were prospectively collected using a predefined electronic form (Figure 1), including both the parameters of the “Morphonode study” and the relevant, additional vascular parameters. We chose to rename some of the parameters according to the corresponding current nomenclature of the international consensus on terms and definitions published by the VITA group (Figure 1) [10 (link),12 (link)].
The subjective assessment of ultrasound variables was applied to all lymph nodes of each groin by using the following classification in five categories: normal (LN1), reactive but negative (LN2), minimally suspicious (LN3), moderately suspicious (LN4), highly suspicious or positive (LN5). Classes LN3–5 were considered positive (potentially metastatic), while classes LN1–2 were considered negative (non-metastatic). If at least one lymph node was classified as LN3–5, the groin was considered positive overall.