Vulvar & Vaginal Pathology
Match each vulvar or vaginal lesion to its histology, age group, and cancer risk
Benign vulvar lesions and dermatoses
Bartholin duct cyst and abscess. Bartholin glands lie in the posterolateral vestibule (about 4 and 8 o'clock) and secrete lubricating mucus. Duct obstruction produces a painless, unilateral cyst; infection produces a tender, red, fluctuant abscess, usually polymicrobial (E. coli, anaerobes) or caused by N. gonorrhoeae or C. trachomatis. Abscesses are drained with a Word catheter, and recurrences are marsupialized. A new Bartholin mass in a woman over about 40 or after menopause is biopsied to exclude carcinoma. Skene (periurethral) lesions sit anteriorly, and Gartner duct cysts (mesonephric remnants) lie in the lateral vaginal wall.
Lichen sclerosus. A chronic, probably autoimmune dermatosis of postmenopausal women (and prepubertal girls) causing intense itch and thin, white, crinkled ("cigarette-paper") skin in a figure-of-eight around the vulva and anus, with resorption of the labia minora and narrowing of the introitus. Histology shows epidermal atrophy with loss of rete ridges, a homogenized, hyalinized upper dermis and a band of lymphocytes beneath it. Ultrapotent topical corticosteroids such as clobetasol control it, and long-term follow-up is needed because it carries a small risk of HPV-independent squamous cell carcinoma. On the penis the same disease is called balanitis xerotica obliterans.
Lichen simplex chronicus. Repeated scratching and rubbing produce squamous hyperplasia: thick, leathery plaques with accentuated skin markings, acanthosis and hyperkeratosis with mild dermal inflammation. It is not premalignant. Because white vulvar lesions (leukoplakia) look alike, any persistent one needs a biopsy.
| Feature | Lichen sclerosus | Lichen simplex chronicus |
|---|---|---|
| Cause | Probably autoimmune | Itch–scratch cycle |
| Epidermis | Thin, lost rete ridges | Thick (acanthosis, hyperkeratosis) |
| Dermis | Hyalinized collagen, lymphocyte band | Mild chronic inflammation |
| Appearance | White parchment-like skin | Leathery lichenified plaques |
| Cancer risk | Increased (HPV-independent SCC) | None |
Vulvar squamous neoplasia
Two pathways. Squamous cell carcinoma makes up about 90% of vulvar cancers and arises by two routes. The HPV-associated route affects younger women, passes through a high-grade squamous intraepithelial lesion (HSIL, usual-type VIN), is linked to HPV-16, smoking and immunosuppression such as HIV, is often multifocal and shows basaloid or warty tumors with block-like p16 staining. The HPV-independent route affects older, usually postmenopausal women, arises on lichen sclerosus through differentiated VIN, carries TP53 mutations, is p16-negative and produces keratinizing, well-differentiated carcinoma.
How HPV transforms. The high-risk E6 protein targets p53 for degradation and E7 inactivates Rb, releasing E2F and driving p16 overexpression, which pathologists use as a surrogate for transforming infection. HSIL shows atypia through most or all of the epithelium and often coexists with cervical, vaginal or anal lesions because the whole anogenital field is infected. Low-grade lesions (flat condyloma) reflect productive infection, and genital warts are mainly HPV-6 and -11.
Differentiated VIN. Its atypia is confined to the basal layers with premature keratinization, so it looks deceptively bland, yet it progresses faster than HSIL. Abnormal p53 staining supports the diagnosis.
Presentation and spread. Vulvar cancer presents as an itchy plaque, ulcer or mass, most often on the labia majora. It spreads first to the superficial inguinal nodes, then to deep inguinal (femoral) and pelvic nodes; depth of invasion and nodal status drive prognosis. Melanoma is the second most common vulvar malignancy, so pigmented lesions are biopsied as well.
Extramammary Paget disease
Clinical picture and pathology. An older woman has a red, crusted, sharply demarcated, itchy plaque, often on the labia majora, mistaken for eczema and unresponsive to topical steroids. Large pale cells with abundant mucin-rich cytoplasm spread singly and in nests through the epidermis, making it an intraepidermal adenocarcinoma. The cells are PAS-positive (diastase-resistant mucin), cytokeratin-positive (CK7), CEA-positive and negative for S-100 and HMB-45; melanoma in situ shows the reverse pattern. Unlike Paget disease of the nipple, which almost always signals an underlying breast carcinoma, vulvar Paget disease usually has no underlying carcinoma, although a minority accompany adnexal, colorectal or urothelial cancers. Tumor cells extend beyond the visible edge, so wide excision is followed by frequent recurrence.
Vaginal tumors
Squamous cell carcinoma. Most vaginal cancers are secondary, spreading from the cervix, endometrium or vulva. Primary vaginal carcinoma is rare and mostly squamous, arising from vaginal intraepithelial neoplasia with HPV-16/18, often in the upper posterior vagina. Lymph from the upper two-thirds drains to iliac nodes and from the lower third to superficial inguinal nodes.
Clear cell adenocarcinoma. Diethylstilbestrol (DES), a synthetic estrogen given in pregnancy until 1971, left Müllerian glandular epithelium in the vaginas of exposed daughters (vaginal adenosis). Adenosis is the precursor of clear cell adenocarcinoma of the vagina or cervix, typically in adolescence or young adulthood, composed of cells with glycogen-rich clear cytoplasm and hobnail nuclei. DES also caused a T-shaped uterus and cervical anomalies.
Sarcoma botryoides. The botryoid variant of embryonal rhabdomyosarcoma affects girls younger than about 4 years as soft, grape-like polypoid clusters protruding from the vagina, often with bleeding. Small round blue cells crowd beneath the epithelium (cambium layer), and rhabdomyoblasts with cross-striations stain for desmin, myogenin and MyoD1. The same tumor arises in the bladder, prostate and biliary tree of young children. Vaginal yolk sac tumor, the main mimic in infants, secretes AFP.