Vulval lesions and FIGO staging
Vulval and vaginal lesions, endometriosis, and grading and staging of gynaecological cancer (FIGO)
This chapter covers the itchy white vulva and its cancer risk, rare vaginal tumours, the pathology of endometriosis, and the difference between grade and stage. CPSP asks which vulval lesions are premalignant, how endometriosis arises and looks, and how FIGO stages common gynaecological cancers.
Benign and premalignant vulval skin disease
| Condition | Clinical picture | Histology | Cancer risk |
|---|---|---|---|
| Lichen sclerosus | Older women; intense itch, worse at night; white, thin, crinkled skin in a figure-of-eight round vulva and anus; labia minora shrink; spares the vagina | Thin epidermis, band of pale hyalinised collagen in upper dermis, lymphocytes beneath | Small (a few per cent); precursor of HPV-negative SCC |
| Lichen simplex chronicus | Itch–scratch cycle; thick, leathery skin | Acanthosis and hyperkeratosis, no atypia | None |
| Erosive lichen planus | Painful erosions, vaginal adhesions and narrowing, white lacy striae in the mouth | Band of lymphocytes hugging the junction, basal damage, saw-toothed rete ridges | Small |
- Lichen sclerosus is treated with an ultrapotent topical steroid (clobetasol propionate 0.05%), which vulval skin tolerates well. Lichen simplex can coexist with it.
- Condyloma acuminatum (raised warty lesions with koilocytes): low-risk HPV 6 and 11.
- Vesicles that ulcerate painfully: herpes simplex. A painless indurated ulcer: primary syphilis.
Vulval intraepithelial neoplasia and cancer
| Pathway | Usual VIN (HSIL) | Differentiated VIN |
|---|---|---|
| Cause | HPV 16 | HPV-independent, on lichen sclerosus |
| Patient | Younger, smokers, often with CIN | Older |
| Markers | Diffuse p16 positive | p53 abnormal |
| Cancer | Basaloid or warty SCC | Keratinising SCC; looks deceptively mild but is more dangerous |
- About 90% of vulval cancers are squamous cell carcinoma, usually on the labia majora; melanoma comes next.
- Lymph drains to the superficial then deep inguinal nodes; midline lesions can spread to both groins.
- Extramammary Paget disease: a red, velvety, eczema-like plaque that does not respond to steroid. Large pale cells with mucin in the epidermis, PAS positive and CK7 positive. It often extends beyond the visible edge, and an underlying adenocarcinoma should be sought.
Vagina
- Most vaginal cancers are secondary (cervix, endometrium, vulva). Primary tumours are rare; squamous cell carcinoma is the commonest.
- FIGO rule: a tumour involving cervix and vagina is classed as cervical; one involving vulva and vagina as vulval.
- Clear cell adenocarcinoma of the vagina follows intrauterine diethylstilboestrol exposure, with vaginal adenosis as the precursor.
- Sarcoma botryoides (embryonal rhabdomyosarcoma): grape-like mass in girls under 5, desmin positive.
- Gartner duct cyst: lateral vaginal wall, a mesonephric (Wolffian) remnant.
Endometriosis
Endometrial glands and stroma outside the uterus; diagnosis needs two of glands, stroma and haemosiderin-laden macrophages.
| Theory | Best explains |
|---|---|
| Retrograde menstruation through the tubes (most accepted) | Ovaries, pouch of Douglas, pelvic peritoneum |
| Coelomic metaplasia | Peritoneal and serosal deposits; cases without menstruation |
| Lymphatic or blood spread | Lung (catamenial haemoptysis), lymph nodes |
| Direct implantation | Caesarean and episiotomy scars |
- Sites: ovary most common, then uterosacral ligaments, pouch of Douglas and pelvic peritoneum. A tender nodule in the posterior fornix means uterosacral disease (deep dyspareunia, painful defecation).
- Appearance: cyclical bleeding leaves haemosiderin, giving blue-black powder-burn spots with puckered fibrosis; early lesions are red or clear vesicles. Ovarian endometriomas are chocolate cysts.
- Symptoms: dysmenorrhoea, deep dyspareunia, dyschezia and subfertility. Severity of pain does not match the amount of disease.
- MRI: endometrioma is bright on T1 and stays bright with fat suppression; on T2 it shows dark layering (shading) from repeated bleeds. Signal that drops on fat suppression suggests a dermoid instead.
- Biology: lesions express aromatase and make their own oestrogen; oestrogen induces COX-2 and PGE2, which induces more aromatase.
- Drugs: progestogens (dienogest) cause decidualisation then atrophy; GnRH agonists cause a hypo-oestrogenic state with bone loss; danazol is androgenic, and deepening of the voice may be permanent.
- Malignant change in an endometrioma gives clear cell (hobnail cells, clear cytoplasm) or endometrioid carcinoma.
Grade versus stage
- Grade = degree of differentiation under the microscope. FIGO grades endometrioid carcinoma by solid non-squamous growth: grade 1 up to 5%, grade 2 6–50%, grade 3 over 50%. Squamous morules are not counted.
- Stage = extent of spread (FIGO or TNM). Stage predicts survival better than grade.
| Cancer | Key FIGO stage boundaries |
|---|---|
| Cervix (2018) | I confined to cervix; II beyond uterus but not lower third of vagina or pelvic wall; III lower vagina, pelvic wall, hydronephrosis, or nodes (IIIC1 pelvic, IIIC2 para-aortic); IV bladder or rectal mucosa, distant |
| Endometrium | IA under half the myometrium; IB half or more; II cervical stroma; III serosa, adnexa, vagina or nodes; IV bladder or bowel mucosa, distant |
| Ovary | I ovaries; II pelvis; III peritoneum outside the pelvis or retroperitoneal nodes (IIIB deposits up to 2 cm, IIIC over 2 cm, including liver surface); IV distant, liver parenchyma, malignant pleural effusion |
| Vulva (2021) | IA 2 cm or less and invasion 1 mm or less; IB larger or deeper; II lower urethra, vagina or anus; III upper structures or mobile nodes; IV fixed or ulcerated nodes, bone, distant |
- Ovarian cancer is staged surgically, most present at stage III, and it spreads first to para-aortic nodes along the ovarian vessels.
Remember Grade is how the cells look; stage is how far they have gone.
Exam trap Lichen sclerosus spares the vagina; vaginal scarring points to erosive lichen planus.
Exam trap Liver surface deposits are ovarian stage III; liver parenchymal deposits are stage IV.
Test yourself on this topic
5 of the 31 questions in our bank on this topic. Choose an answer to see why every option is right or wrong.
A 74-year-old woman with long-standing vulval lichen sclerosus develops an ulcerated nodule; biopsy shows keratinising squamous cell carcinoma, and tests for HPV are negative. Through which pathway did this cancer most likely arise?
Answer: Differentiated VIN, HPV-independent
Vulval squamous cancer arises by two pathways. In older women it is usually HPV-independent, develops on lichen sclerosus through differentiated VIN (often with TP53 mutation), and is keratinising. In younger women it is HPV-associated (mainly HPV 16), develops through usual-type VIN (HSIL) and tends to be basaloid or warty. HPV-negative keratinising cancer on lichen sclerosus therefore fits the first pathway.
Two roads to vulval cancer
- Older: lichen sclerosus
- Differentiated VIN, HPV-negative
- Younger: HPV 16, usual VIN
- Keratinising vs basaloid
Remember Old woman, lichen sclerosus, HPV-negative: differentiated VIN.
Exam trap Differentiated VIN can look deceptively mild but is the more dangerous precursor.
Why the other options are wrong
- Usual-type VIN driven by HPV 16 Younger women, HPV-positive, basaloid tumours.
- Malignant change in Bartholin gland Would arise deeper as an adenocarcinoma or similar.
- Invasion from extramammary Paget Gives adenocarcinoma, not keratinising SCC.
- Transformation of a basal cell lesion Basal cell carcinoma is a different tumour.
A 55-year-old woman has a squamous cell carcinoma that involves both the ectocervix and the upper vagina, and it is unclear where it began. Under FIGO rules, how is this tumour classified?
Answer: As a primary cervical carcinoma
FIGO rules state that a tumour involving the cervix and vagina is classified as cervical cancer, and one involving the vulva and vagina is classified as vulval cancer. A diagnosis of primary vaginal carcinoma therefore needs the cervix and vulva to be free of tumour. This is why true primary vaginal cancer is rare, while secondary involvement of the vagina, especially from the cervix, is common.
FIGO site rules
- Cervix + vagina: cervical cancer
- Vulva + vagina: vulval cancer
- Primary vaginal needs cervix and vulva clear
- Most vaginal tumours are secondary
Remember When vagina and cervix share a tumour, the cervix gets the name.
Exam trap Calling such a tumour vaginal changes its staging and treatment plan.
Why the other options are wrong
- As a primary vaginal carcinoma Needs the cervix and vulva to be free.
- As two separate primary tumours Not the FIGO convention.
- As a vulvovaginal carcinoma Applies only when vulva and vagina are involved.
- As carcinoma of unknown primary Not the FIGO convention.
Blue-black 'powder-burn' spots with puckered scarring are seen on the pelvic peritoneum at laparoscopy for cyclical pain. Which pigment colours them?
Answer: Haemosiderin from old bleeding
Endometriotic implants respond to the cycle and bleed each month. The blood cannot escape, and macrophages break down the haemoglobin and store its iron as haemosiderin, giving blue-black or brown 'powder-burn' lesions. The inflammation causes fibrosis and puckering of the surrounding peritoneum. Haemosiderin-laden macrophages are also a supporting histological sign of endometriosis.
Powder-burn lesions
- Implants bleed cyclically
- Macrophages store haemosiderin
- Blue-black, puckered spots
- Fibrosis and adhesions
Remember Dark spots of endometriosis are old blood.
Exam trap Early lesions are often red or clear vesicles, not black, and are easily missed.
Why the other options are wrong
- Melanin from pigmented cells Melanocytes are not part of implants.
- Lipofuscin from ageing cells Wear-and-tear pigment, not old blood.
- Bilirubin from red cell breakdown Not stored in these lesions.
- Carbon from previous diathermy No previous surgery in this case.
A 46-year-old woman with long-standing endometriosis has a solid nodule growing from the wall of an endometriotic cyst. Histology shows sheets and tubules of cells with abundant clear, glycogen-rich cytoplasm and 'hobnail' nuclei bulging into the lumen. What is the diagnosis?
Answer: Clear cell carcinoma
Clear glycogen-rich cells with hobnail nuclei form a clear cell carcinoma. This tumour and endometrioid carcinoma are the ovarian cancers most strongly linked to endometriosis, often arising in an endometrioma; ARID1A loss is common in both. Dysgerminoma has clear cells too, but occurs in young women with lymphocytic septa. Yolk sac tumour affects young women and has Schiller–Duval bodies.
Cancer from endometriosis
- Endometrioma can turn malignant
- Clear cell and endometrioid types
- Hobnail cells, clear cytoplasm
- ARID1A loss common
Remember Endometriosis-related ovarian cancer: clear cell or endometrioid.
Exam trap Clear cytoplasm alone is not specific; age, hobnails and the endometrioma point to clear cell carcinoma.
Why the other options are wrong
- Dysgerminoma Young women; lymphocytic septa, no hobnails.
- Serous cystadenocarcinoma Papillae and psammoma bodies, no clear hobnail cells.
- Mucinous carcinoma Mucin-filled columnar cells.
- Yolk sac tumour Young patients; Schiller–Duval bodies.
Two 55-year-old women have high-grade serous ovarian carcinoma of identical histology and grade. One has disease confined to one ovary; the other has omental and diaphragmatic deposits. Which single factor best predicts the difference in their survival?
Answer: FIGO stage at diagnosis
For most carcinomas, including ovarian, cervical, endometrial and vulval cancer, the stage at diagnosis is the strongest predictor of survival. Stage reflects tumour burden and spread, which determine whether all disease can be removed and how likely recurrence is. Grade adds prognostic information but is identical here. CA-125 rises with tumour volume but is not independent of stage, and age is the same in both.
Stage predicts survival
- Stage = extent of spread
- Strongest prognostic factor
- Grade adds less
- Most ovarian cancer presents at stage III
Remember How far it has spread matters more than how it looks.
Exam trap Staging is surgical in ovarian cancer, so incomplete surgery can understage the disease.
Why the other options are wrong
- Histological tumour grade Same in both women.
- Pre-operative CA-125 level Tracks tumour bulk; not the best independent predictor.
- Age at diagnosis Same in both women.
- Number of mitoses per field Part of grade, which is the same.
Where this sits in the CPSP syllabus
- Obstetrics & Gynaecology, Paper 2: Neoplasia of the female genital tract, Vulval and vaginal lesions; endometriosis; grading and staging of cancer (FIGO)