Patterns of keratinocyte carcinoma incidence on the scalp and forehead of non-alopecic women: a retrospective review

Keratinocyte carcinomas are the most frequently diagnosed form of malignancy, and ultraviolet radiation exposure is a primary risk factor. Human head hair offers some protection from ultraviolet radiation, and women often wear hairstyles that result in variable scalp exposure to sunlight. The distribution of keratinocyte carcinomas of the forehead and scalp of women has not been previously studied. To better characterize the incidence and distribution of keratinocyte carcinomas on the scalp and forehead of non-alopecic females, a retrospective chart review was performed of keratinocyte carcinomas diagnosed and treated at a single tertiary care center between July 2017 and October 2021. Tumor and patient characteristics were compiled and analyzed. 302 cases of keratinocyte carcinomas occurring on the scalp and forehead of non-alopecic women were identified. Basal cell carcinoma occurred at a higher rate than squamous cell carcinoma (231 vs. 71). Both basal cell carcinomas and squamous cell carcinomas were more likely to occur within the part line on the scalp (p = 0.036). There was also an increased risk of developing keratinocyte carcinomas on the upper third of the forehead, although this observation did not reach statistical significance (p = 0.165). Keratinocyte carcinomas of the scalp and forehead are more likely to occur in the part line of the scalp. This information can guide dermatologists during clinical exams and when counseling patients on performing proper sun-protective measures.