Vulvar Cancer: 2021 Revised FIGO Staging System and the Role of Imaging

Abstract

Vulvar cancer is a rare gynecological malignancy. It constitutes 5-8% of all gynecologic neoplasms, and squamous cell carcinoma is the most common variant. This article aims to review the etiopathogenesis revised 2021 International Federation of Gynecology and Obstetrics (FIGO) classification and emphasize imaging in the staging of vulvar cancer. The staging has been regulated by FIGO since 1969 and is subjected to multiple revisions. Previous 2009 FIGO classification is limited by the prognostic capability, which prompted the 2021 revisions and issue of a new FIGO classification. Although vulvar cancer can be visualized clinically, imaging plays a crucial role in the staging of the tumor, assessing the tumor extent, and planning the management. In addition, sentinel lymph node biopsy facilitates the histopathological staging of the draining lymph node, thus enabling early detection of tumor metastases and better survival rates.

Keywords: 2021 vulvar cancer staging; FIGO staging; imaging of vulvar cancer.

Figure 1

(A) Normal anatomy of vulvar region. (B) Normal description of location of lesions. (C) Regional and non-regional lymph nodes of the vulva. (D–F) Axial non-fat saturated T2-weighted images (WI) of a 36-year-old-female with normal anatomy. Image D demonstrates labia majora (long thick arrow) and labia minora (short, thin arrow). Image E shows the bulb of the vestibule (short, thin arrow), glans (asterisk), and crus (long thin arrow) of the clitoris. Image F demonstrates the ischiocavernosus muscle (dotted arrow).

Figure 2

Revised 2021 FIGO staging of vulvar cancer. Stage I tumor confined to the vulva. (A) Stage IA tumor size less than equal to 2 cm and stromal invasion less than equal to 1 mm. (B) Stage IB tumor size more than 2 cm and stromal invasion more than 1 mm. (C) Stage II tumor of any size with extension to lower one-third of the urethra, lower one-third of the vagina, lower one-third of the anus with negative nodes. Stage III tumor of any size with extension to the upper part of adjacent perineal structures or with any number of nonfixed, nonulcerated lymph nodes. (D) Stage IIIA tumor of any size with disease extension to the upper two-thirds of the urethra, upper two-thirds of the vagina, bladder mucosa, rectal mucosa, or regional lymph node metastases less than equal to 5 mm. (E) Stage IIIB regional lymph node metastases more than 5 mm. (F) Stage IIIC regional lymph node metastases with extracapsular spread. Stage IV tumor of any size fixed to bone or fixed, ulcerated lymph node metastases, or distant metastases. (G) Stage IVA disease fixed to the pelvic bone or fixed or ulcerated regional lymph node metastases. (H) Stage IVB distant metastases.

Figure 3

FIGO stage IA. A 43-year-old female with squamous cell carcinoma of the vulva. (A) Axial T2 weighted image and (B) post-contrast fat-saturated axial T1 weighted MRI image showing an enhancing 1.3 × 0.6 cm T2 intermediate signal biopsy-proven vulvar tumor (arrow).

Figure 4

FIGO stage IB. A 52-year-old female with squamous cell carcinoma of the vulva. (A) Axial T2 weighted image and (B) post-contrast fat-saturated axial T1 weighted MRI image showing an enhancing 3.4 × 2.3 cm T2 intermediate signal biopsy-proven vulvar tumor (arrow).

Figure 5

FIGO stage II. A 57-year-old female with squamous cell carcinoma of the vulva. (A) Axial T2 weighted image and (B) coronal T2 weighted MRI image show a 3.4 × 1.4 cm vulvar tumor (asterisk) involving the right aspect of the lower one-third of the vagina (long thin arrow) and right ischio-anal fossa (short thick arrow). Anteriorly, the mass abuts the lower third of the urethra. No lymphadenopathy was noted. Note that the gel in the vagina helps better delineate the tumor.

Figure 6

FIGO stage III. A 49-year-old female with squamous cell carcinoma of the vulva. Axial T2 weighted MRI image shows infiltrative vulvar tumor (asterisk) involving, anteriorly, the lower one-third of the urethra (long thin arrow) and, posteriorly, the lower one-third of the anus (long thick arrow). Moreover, there is a metastatic right inguinal lymph node (short thick arrow). The findings correspond to FIGO stage IIIB.

Figure 7

FIGO stage IV. A 56-year-old female with squamous cell carcinoma of the vulva. (A) post-contrast fat-saturated axial T1 weighted MRI image shows an enhancing 5.2 × 2.8 cm vulvar tumor (asterisk). (B) Coronal lung window contrast-enhanced CT image shows pulmonary nodule (arrow). A biopsy of the nodule was positive for metastasis. The findings correspond to FIGO stage IVB.

Figure 8

Primary treatment of vulvar cancer.

Figure 9

Post-surgical surveillance of vulvar cancer.

Figure 10

Lymph node evaluation and treatment in patients with vulvar cancer.

Figure 11

Treatment response assessment. A 55-year-old female with recurrent vulvar squamous cell carcinoma. (A) Axial and (B) sagittal T2 weighted MRI images show a large vulvar mass (asterisk) invading both the low rectum (thick arrow) and diffusely throughout the left semi circumferential anal canal (not shown), with additional invasion along the left posterolateral aspect of the upper two-thirds of the vagina (thin arrow). No evidence of enlarged lymph nodes. The findings correspond to FIGO stage IIIA. A Follow-up MRI after three months of chemoradiation was obtained. (C) Axial and (D) sagittal T2 weighted image MRI show an interval decrease in the size of the treated left vulvar mass invading the lower rectum, anal canal, left upper one-third of the vagina, and left lateral pelvic sidewall. (b, bladder; v, vagina; r, rectum).