Clinical overview
The vagina is an uncommon primary site for neoplasia, and that single fact dominates everything you say about vaginal tumours in the FCOG(SA) exam. Primary vaginal carcinoma accounts for only 1–2% of all gynaecological malignancies; the overwhelming majority of malignant tumours found in the vagina are secondary — direct extension from cervix, vulva, endometrium, bladder or rectum, or metastatic deposits. The diagnostic discipline that follows is strict: a malignancy is classified as primary vaginal only when the cervix and vulva are not involved, because if either is involved the lesion is classified as a cervical or vulvar primary by convention. This is not pedantry — it changes the staging system, the field of treatment, and the prognosis.
Benign vaginal tumours and tumour-like lesions are, by contrast, common and mostly inconsequential: epithelial inclusion cysts, Gartner duct (mesonephric) cysts, müllerian cysts, fibroepithelial polyps, and the occasional leiomyoma. The clinical art is separating a benign cyst or polyp that can be reassured or simply excised from the rare malignant lesion that demands biopsy and referral. In the South African context two further threads run through this topic and recur in the exam: the dominant role of HPV in vaginal squamous neoplasia in a population with very high HIV prevalence, and the historical but examinable association of clear cell adenocarcinoma with in-utero diethylstilboestrol (DES) exposure. This chapter is weighted, as the objective demands, toward pathological features — gross and microscopic — of both benign and malignant vaginal tumours, with the assessment and management sections kept to principles. It links closely to HPV pathology, Cervical carcinogenesis, Cervical screening SA, Vulval carcinoma and Genital tract cysts.
Core knowledge
Anatomy and field considerations
The vagina is a fibromuscular tube lined by non-keratinised stratified squamous epithelium over a lamina propria, then a muscularis (inner circular, outer longitudinal smooth muscle) and an adventitia. There are no glands in the normal vaginal wall — mucus comes from the cervix and Bartholin glands — so a glandular lesion in the vagina is intrinsically abnormal and points to embryonic remnants (mesonephric/müllerian), adenosis, endometriosis, or adenocarcinoma. The upper two-thirds drains lymph to the pelvic (obturator, internal/external iliac) nodes and the lower third to the inguinofemoral nodes — a split that mirrors the embryological junction and explains the dual nodal spread of vaginal cancer depending on tumour level.
Benign tumours and tumour-like lesions
Figure D12.1 — Benign vaginal tumours and cysts: Gartner duct, Müllerian, squamous papilloma and fibroepithelial polyp — origin, appearance and the always-send-histology rule.
These are best learned as a short, gross-plus-microscopic list, because the exam tests recognition.
- Epithelial inclusion (epidermoid) cyst — the commonest vaginal cyst; usually in the lower posterior/lateral wall, often at a site of prior obstetric laceration or episiotomy repair where squamous epithelium is buried. Gross: small, firm, mobile. Micro: lined by stratified squamous epithelium with keratin debris. Benign; excise only if symptomatic.
- Gartner duct cyst — a mesonephric (Wolffian) remnant; characteristically along the anterolateral vaginal wall. Micro: lined by low cuboidal/columnar non-mucinous, non-ciliated epithelium. Usually asymptomatic; can rarely enlarge or become infected.
- Müllerian (paramesonephric) cyst — derived from müllerian remnants; lined by mucinous endocervical-type, tubal-type ciliated, or endometrioid epithelium. The presence of mucin/cilia distinguishes it from a Gartner cyst.
- Bartholin duct cyst/abscess — strictly at the introitus (vestibule), but classically examined alongside; lined by transitional/squamous epithelium.
- Fibroepithelial polyp — a benign stromal-epithelial polyp; soft, pedunculated. Micro: oedematous fibrovascular core covered by squamous epithelium, sometimes with bizarre but benign stromal cells (a recognised diagnostic pitfall — do not overcall as sarcoma).
- Vaginal leiomyoma — the commonest benign solid mesenchymal tumour of the vagina; arises from the muscularis. Gross: firm, whorled, well-circumscribed. Micro: interlacing fascicles of bland spindle smooth-muscle cells, low mitotic count, no atypia/necrosis.
- Vaginal adenosis — not a tumour but a key precursor concept: glandular (columnar müllerian) epithelium present in the vagina where there should be none. Strongly associated with in-utero DES exposure, and the soil from which clear cell adenocarcinoma can arise.