- SCC in-situ = Pre-malignant
- Pathology
- Diagnosed when keratinocyte dysplasia is full thickness of the epidermis without infiltration into the dermis (through the basement membrane)
- Keratinocytes show pleomorphism, hyperchromatic nuclei, and nuclear mitosis.
- Frequently there is associated thickening of the epidermis.
- Clinical
- Reddened area with plaque like thickening
- Can cover large areas
- Rough, scaly, erythematous macules which develop on sun-damaged skin and demonstrate keratinocyte atypia
- Progression
- The rate of transformation to an SCC is low - about 1% per year
- Progression to invasion 15-20 years (1:1000 lesion/year)
- 5% show invasion at time of removal
- Bowen’s disease of the penis
- Erythroplasia of Queyrat
- Erythroplasia of Queyrat
Treatment of Bowen disease
- Surgery - 4mm margin
- Topical
- Topical 5-Fluorouracil 5% - BD for 4 weeks.
- Imiquimod
- Stimulate an immune response thus area will become inflammed - this indicates the cream is likely to be effective.
- Cryotherapy
- Currettage and electrodessication