Vaginal Malignancy

Descriptive text is not available for this image BASICS

DESCRIPTION

  • Primary carcinomas of the vagina are rare: 2–3% of gynecologic malignancies and 1,372 new cases annually in the United States as of 2021 (1)
  • Vaginal intraepithelial neoplasia (VAIN), the precursor lesion for vaginal cancer, is defined by squamous cell atypia and is classified by the depth of epithelial involvement (2)
    • VAIN 1: 1/3 thickness
    • VAIN 2: 2/3 thickness
    • VAIN 3: >2/3 thickness
    • Carcinoma in situ (CIS): designating full-thickness neoplastic changes without invasion through the basement membrane
  • Invasive malignancies: Vaginal malignancies include squamous cell carcinoma (85–90%), adenocarcinoma (5–10%), sarcoma (2–3%), and melanoma (2–3%). Clear cell carcinoma is a subtype of adenocarcinoma. Invasive vaginal cancer can spread by direct extension to adjacent tissues, lymphatic dissemination to locoregional lymph nodes (pelvic and para-aortic, or inguinal), or via hematogenous squamous cell carcinoma; has the potential for hematogenous metastasis to other sites including the lungs and liver.
  • To be classified as a primary vaginal malignancy, only the vagina can be involved. If the cervix or vulva is involved, then the tumor is classified as a primary cancer arising from the cervix or the vulva. Additionally, if the patient has had a diagnosis of invasive cervical or vulvar cancer in the preceding 5 years, it cannot be classified as a primary vaginal malignancy.
  • If the patient has a cervix, then a primary cervical malignancy should be conclusively ruled out before vaginal cancer diagnosis can be made.
  • Most vaginal malignancies are metastatic tumors from other primary sites (e.g., cervix, vulva, endometrium).

Pregnancy Considerations
This malignancy is not typically associated with pregnancy (3).

EPIDEMIOLOGY

Incidence

Predominant age is dependent on type:

  • CIS: mid-40 to 60 years
  • Invasive squamous cell malignancy: mid-60 to 70 years
  • Adenocarcinoma: can occur at any age; 50 years is the mean age, with peak incidence between 17 and 21 years of age.
  • Clear cell adenocarcinoma occurs most often in females aged <30 years with a history of exposure to diethylstilbestrol (DES) in utero.
  • Mixed Müllerian sarcomas and leiomyosarcomas in the adult population: mean age is 60 years.

Pediatric Considerations
Vaginal tumors are extremely rare. Rhabdomyosarcoma (botryoid and embryonal subtype) is the most common malignant neoplasm of the vagina in children, and can be part of a cancer syndrome (NF-1, Li-Fraumeni, Beckwith-Wiedemann). Less common entities are germ cell tumor and clear cell adenocarcinoma.

Prevalence

In the United States, it is one of the rarest of all gynecologic malignancies

ETIOLOGY AND PATHOPHYSIOLOGY

  • Women with a history of cervical malignancy have a higher probability of developing squamous cell malignancy in the vagina, even after hysterectomy.
  • Human papillomavirus (HPV) is found in 80–93% of patients with vaginal CIS and 50–65% of the patients with invasive vaginal carcinoma.
  • HPV-16 is the most common, found in 66% of CIS and 55% of invasive vaginal cancers.
  • There is a higher risk of vaginal cancer in patients who smoke cigarettes.
  • Clear cell adenocarcinoma of the vagina in young women has been associated with DES exposure in utero. The incidence, however, is exceedingly rare, estimated at 1/1,000 to 1/10,000 exposed females.
  • Metastatic lesions can involve the vagina, spreading from the other gynecologic organs.
  • Although rare, renal cell carcinoma, lung adenocarcinoma, GI cancer, pancreatic adenocarcinoma, ovarian germ cell cancer, trophoblastic neoplasm, and breast cancer can all metastasize to the vagina

Genetics

There is no known genetic pattern

RISK FACTORS

  • Similar risk factors as cervical cancer, including smoking, HPV exposure, immunodeficiency
  • Age
  • African American
  • Multiple sex partners, early age of first sexual intercourse
  • History of squamous cell cancer of the cervix or vulva
  • Vaginal adenosis, often associated with DES exposure
  • Vaginal irritation
  • DES exposure in utero
  • Prior pelvic radiation

COMMONLY ASSOCIATED CONDITIONS

Due to field effect, patients with vaginal cancer are more likely to develop malignancy in the cervix or vulva and should be followed closely.

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