Dermatoscopy of facial actinic keratosis, intraepidermal carcinoma, and invasive squamous cell carcinoma: a progression model.

BACKGROUND Little is known about the dermoscopic features of keratinocyte skin cancer. OBJECTIVE We sought to determine the dermoscopic features of facial actinic keratosis (AK), intraepidermal carcinoma (IEC), moderately to poorly differentiated invasive squamous cell carcinoma (SCC), and well-differentiated SCC of the keratoacanthoma type. METHODS This was a retrospective analysis of dermoscopic images of histopathologically diagnosed keratinocyte skin cancer. RESULTS A total of 243 (70 AK, 71 IEC, 78 SCC, and 24 keratoacanthomas) tumors of the face from 243 patients (mean age: 71.1 years; range: 44-94 years) were analyzed. The majority of patients had a fair skin type, history of melanoma or nonmelanoma skin cancer, and multiple AK. A red pseudonetwork was significantly associated with AK (P < .001), whereas dotted/glomerular vessels, diffuse yellow opaque scales, and microerosions were significantly more prevalent among IEC (P < .001). Hairpin vessels, linear-irregular vessels, targetoid hair follicles, white structureless areas, a central mass of keratin, and ulceration were significantly associated with invasive SCC (P < .001 for all criteria). Similar patterns as in SCC were observed among keratoacanthomas. LIMITATIONS The retrospective design of our study and the lack of assessment of sensitivity and specificity of the dermoscopic criteria are limitations. CONCLUSIONS Based on our findings we propose a progression model of facial AK developing into IEC and invasive SCC.