SLN mapping using indocyanine green (ICG) with near-infrared fluorescence imaging is a promising staging alternative in gynecologic malignancies and has been validated in patients with endometrial and cervical cancers [5,6]. Based on this evidence, this technique has been extended to vulvar cancers. Recently, several studies have shown the feasibility, accuracy, and safety of SLN mapping using ICG with near-infrared fluorescence imaging in vulvar cancer [7,8].

A 40-year-old woman was referred to our hospital for cancer in the left vulva that was diagnosed at another hospital in March 2020. She had no specific medical history other than two induced abortions. The vulvar biopsy specimen was reviewed by a gynecologic pathologist at our institute; adenoid cystic carcinoma was subsequently diagnosed. A baseline study was performed: Pap smear results showed adenoid cystic carcinoma, human papillomavirus genotyping revealed negative findings, and tumor markers were within the normal range. Examination of the vulvar mass lesion by colposcopy revealed an ulcerative and palpable mass, approximately 3 cm in size, in the left vulva. Pelvic contrast-enhanced magnetic resonance imaging showed small ulcerative enhancing lesions of approximately 3.4 cm in the left vagina; these were predicted to be International Federation of Gynecology and Obstetrics (FIGO) stage II. F-18 fluorodeoxyglucose (FDG) positron-emission tomography-computed tomography showed mild FDG uptake in the left vulva area, suggesting postoperative change; however, residual tumors could not be excluded. In both images, there was no evidence of metastasis to the lymph nodes or other organs. Esophagogastroduodenoscopy, colonoscopy, and breast sonography revealed no tumors in the upper gastrointestinal tract, colon, or breast, respectively. Under the diagnosis of vulvar cancer, the patient was scheduled to undergo radical vulvectomy and ICG fluorescent image-guided inguinal SLN biopsy. Approximately 3 mL of ICG (1.25 mg/mL) was directly injected into the vulvar mass for lymphatic drainage mapping. A 4-cm linear incision was made on the left inguinal crease, lymphatic channels were dissected, and an SLN was identified using the 1588 Advanced Imaging Modalities Platform laparoscopic camera (Stryker, Kalamazoo, MI, USA). After removing the left inguinal SLN, the node was sent out for frozen section diagnosis, which revealed few atypical cell clusters. The operation was completed after radical vulvectomy with an adequate resection margin. However, the final pathology result showed metastasis to the left inguinal SLN, indicating vulvar cancer, FIGO stage IIIA. The patient then received radiation therapy to the inguinal area and was monitored for 16 months without recurrence.

The advantages of SLN mapping using ICG with near-infrared fluorescence imaging include easier application, absence of radioactivity, and fewer side effects [8]. In addition, the procedure is less invasive, with little pain and scarring.

SLN biopsy is recommended as the standard treatment for women with early-stage vulvar cancer [9]. Comba et al. [10] showed that videoendoscopic SLN biopsy in vulvar cancer is a feasible procedure, and there may be increased usage of SLNs in early stage vulvar cancer with a videoendoscopic approach. However, this case demonstrated that the use of ICG with near-infrared fluorescence imaging for SLN biopsy is effective even at advanced stages. Gu et al. [11] reported that appropriate adjuvant radiotherapy SLN biopsy alone provided similar long-term survival to inguinofemoral lymphadenectomy for patients with or without sentinel node metastasis.

In conclusion, this video demonstrates that ICG fluorescent image-guided inguinal SLN biopsy using a laparoscopic fluorescence imaging system could be applied in vulvar cancer. Mapping of inguinal SLNs in vulvar cancer patients may help in retaining surgical radicality while minimizing operative complications.