Most squamous carcinomas of the vulva occur on the labia majora and minora (60%), but the clitoris (15%) and perineum (10%) may be primary sites. Approximately 10% of the cases are too extensive to determine a site of origin, and about 5% of the cases are multifocal.
As part of the clinical evaluation, a careful assessment of the extent of the lesion, including whether it is unifocal or multifocal, should be performed. The groin lymph nodes should be evaluated carefully, and a complete pelvic examination should be performed. A cytologic sample should be taken from the cervix, and colposcopy of the cervix and vagina should be performed because of the common association with other squamous intraepithelial or invasive neoplasms of the lower genital tract.
Diagnosis Diagnosis requires a Keys punch biopsy or wedge biopsy, which can be obtained in the office using local anesthesia. The biopsy must include sufficient underlying dermis to assess for microinvasion.
Physician delay is a common problem in the diagnosis of vulvar cancer, particularly if the lesion has a warty appearance. Any large or conﬂuent warty lesion requires biopsy before medical or ablative therapy is initiated.
Routes of Spread Vulvar cancer spreads by the following routes: 1.
Direct extension, to involve adjacent structures such as the vagina, urethra, and anus.
2.
Lymphatic embolization to the regional inguinal and femoral lymph nodes.
3.
Hematogenous spread to distant sites, including the lungs, liver, and bone.
Lymphatic metastases may occur early in the disease. Twelve percent of tumors 2 cm in diameter or smaller have regional metastases (32,36). Initially, spread is usually to the inguinal lymph nodes, which are located between Camper’s fascia and the fascia lata (37). From these superficial groin nodes, the disease spreads to the deep femoral nodes, which are located medial to the femoral vessels (Fig. 38.3). Cloquet’s or Rosenm¨ uller’s node, situated beneath the inguinal ligament, is the most cephalad of the femoral node group. Metastases to the femoral nodes without involvement of the inguinal nodes is reported (38–41). A study from the
M. D. Anderson Cancer Center reported a 9% groin recurrence rate in 104 patients with vulvar cancer who had negative nodes on superficial inguinal lymphadenectomy at initial surgery, and intraoperative lymphatic mapping studies found the sentinel node deep to the cribriform fascia in 5% to 16% of these cases (42–44).
From the inguinal-femoral nodes, the cancer spreads to the pelvic nodes, particularly the external iliac group. Although direct lymphatic pathways from the clitoris and Bartholin gland to the pelvic nodes were described, these channels seem to be of minimal clinical significance (45–47). The lymphatics from either side of the vulva form a rich network of anastomoses along the midline. Lymphatic drainage from the clitoris, anterior labia minora, and perineum is bilateral. Metastases to contralateral lymph nodes in the absence of ipsilateral nodal involvement is very rare (0% to 0.4%) for lateral vulvar tumors that are either 2 cm or less in diameter or with 5 mm or less invasion (36,48).