Vulval lichen sclerosus and the focal ulcer — structured SAQ (15 marks)

(a) Diagnosis and complication (3 marks)

1 mark for the dermatosis, 1 mark for the complication, 1 mark for the reasoning. ^[4]

• Dermatosis: vulvar lichen sclerosus. The porcelain-white atrophic plaques in a figure-of-eight distribution with ecchymoses, labial fusion, clitoral burying and vaginal sparing are the classic presentation.
• Complication of the ulcer: vulvar intraepithelial neoplasia (differentiated or usual-type) or invasive squamous cell carcinoma until biopsy proves otherwise. A focal, non-healing ulcer resistant to appropriate topical corticosteroid is a re-biopsy trigger.
• Reasoning: the chronicity of her lichen sclerosus places her at an elevated lifetime SCC risk; the treatment-resistant focal ulcer is the highest-yield exam answer for neoplasia.^[1][3]

(b) Diagnostic procedure and technique (3 marks)

• Procedure: a punch biopsy of the ulcer for histopathology, with direct immunofluorescence only if an autoimmune blistering disorder is in the differential. ^[1]
• Technique: a 4 mm punch biopsy under local anaesthetic. ^[1]
• Site: the active edge of the ulcer or lesion, not the centre of an erosion, with the deepest tissue from the most abnormal area sent for dermatopathology. ^[1][4]

(c) First-line treatment of vulvar lichen sclerosus (4 marks)

1 mark for each of agent, vehicle, potency and induction regimen. ^[1][2]

• Agent: clobetasol propionate. ^[1]
• Vehicle: ointment (preferred to cream — better penetration, fewer preservatives). ^[1]
• Potency: ultrapotent (Class I) topical corticosteroid. ^[1]
• Induction regimen: clobetasol propionate 0.05% ointment once daily for about 4 weeks, then a tapering course over the following weeks (e.g. alternate days, then twice weekly) guided by clinical response, with a maintenance regimen of a tapered application (e.g. two to three times weekly) and regular clinical review.^[1][2]

(d) SCC risk and surveillance plan (3 marks)

• SCC risk: approximately 4 percent lifetime risk of vulvar squamous cell carcinoma (the Vieira-Baptista 2022 systematic review of 14,372 women; higher in the first 1-3 years after a biopsy, with advancing age and in the presence of differentiated VIN; lower with ultrapotent corticosteroid use).^[3]
• Surveillance plan: lifelong 6-12 monthly clinical review with biopsy of any focal change, with the highest vigilance in the first three years after diagnosis and in older women.^[1][3]

(e) Two further management actions (2 marks)

1 mark each, up to two. ^[1]

• Reassess the patient for adherence to her current corticosteroid regimen and counsel about the diagnosis and prognosis.
• Order a baseline autoimmune screen (thyroid function and thyroid autoantibodies, vitamin B12, folate, fasting glucose) given the autoimmune associations of lichen sclerosus.
• General vulval care measures: a soap substitute and emollient, loose cotton underwear, lubricants for intercourse, saline Sitz baths for the acute fissuring.
• Refer to a multidisciplinary vulval service linking gynaecology, dermatology and pathology.

Common errors that lose marks

• Calling the focal ulcer a "lichen sclerosus flare" and not biopsying — the cardinal error of the topic.
• Prescribing a low-potency or moderate-potency corticosteroid — the first-line is ultrapotent.
• Prescribing a cream rather than an ointment.
• Quoting the SCC rate as 1 percent or 10 percent — the contemporary estimate is approximately 4 percent.
• Offering prophylactic vulvectomy — surgery has no role in disease control; recurrence is invariable.
• Recommending topical testosterone — no longer recommended.
• Missing the figure-of-eight distribution or saying the vagina is involved (vaginal sparing is diagnostic of LS).^[1][3]

Examiner notes

A high-scoring candidate defends the biopsy rule (biopsy at first presentation; re-biopsy any focal ulcer, plaque, treatment-resistant or new lesion), names clobetasol propionate 0.05% ointment as the first-line ultrapotent corticosteroid, quotes the approximately 4 percent SCC risk from the Vieira-Baptista 2022 systematic review, and commits to lifelong 6-12 monthly surveillance.^[1][3]