Pre-malignantICD-10 D04
Bowen's disease
Squamous cell carcinoma in situ; intraepidermal carcinoma
In-situ cutaneous SCC with full-thickness epidermal dysplasia. Risk of progression to invasive cSCC is approximately 3% over the long term (older series quote 3–5% lifetime risk; modern per-annum risk < 1% per lesion), higher at sites of chronic sun damage, immunosuppression and prior radiotherapy.
CurrentLast reviewed 15 March 2026
Management
Non-surgical
- Topical 5-FU 5% — 4–6 weeks bd; high clearance, cheap.
- Imiquimod 5% — daily for 6–16 weeks; suitable for larger areas.
- MAL-PDT — first-line for large, lower-limb, or poor-healing sites; 1–2 sessions.
- Cryotherapy — small, well-defined lesions; avoid on lower leg where possible.
Surgical
- Curettage & cautery — small hyperkeratotic lesions.
- Excision — when invasion suspected or previously failed non-surgical therapy; 4 mm margin usually sufficient for purely in-situ disease.
References
- Morton CA et al. British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma in situ (Bowen disease) 2022. Br J Dermatol. 2023;188(2):186-194.
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