Definition
- Precancerous scaly spot found on sun-damaged skin
- Demonstrate keratinocyte atypia
- Early form of cutaneous squamous cell carcinoma (a keratinocyte cancer)
Clinical
- Examination
- A flat or thickened papule, or plaque
- White or yellow; scaly, warty, or horny surface (can have Keratotic Horn)
- Skin coloured, red, or pigmented
- Tender or asymptomatic
- Location
- Exposed to the sun, especially the backs of the hands and the face, most often affecting the ears, nose, cheeks, upper lip, vermilion of the lower lip, temples, forehead, and balding scalp
Cause
- Sun damage
Pathology
- Dysplasia & architectural disorder of the lowermost layers of the epidermis
- (cf SCC: Atypia in all layers of epidermis)
- Parakeratosis – retention of nuclei in keratin layer
Transformation
- The rate of transformation to an SCC is low - about 0.1% per year
Diagnosis
- Clinically
- Dermoscopy
- Rarely biopsy
Management
- Cryotherapy
- Liquid nitrogen
- 5-10sec / until lesion goes white x 3
- Lesions become irritated, ulcerate & slough
- Liquid nitrogen
- Shave, curettage and electrocautery
- Excision
- Topical
- 5-Fluorouracil
- Imiquimod
- Photodynamic therapy
