Snapshot A 67-year-old man with male-patterned baldness comes to the dermatologist. He realized recently that the skin on his scalp was not smooth. He describes it as feeling rough, like “sandpaper.” While he is now retired, he was a gardener and often spent hours under the sun. Introduction Keratotic, pre-malignant lesions Epidemiology common in fair-skinned individuals common in elderly patients results from significant lifetime sun exposure keratinocyte damage May lead to squamous cell carcinoma Presentation Symptoms typically asymptomatic occasionally tender Physical exam thin, adherent transparent or yellow scale that progressively increases in thickness often with telangiectasias can progress to cutaneous horn difficult to distinguish from squamous cell carcinoma at this point rough, “sand-paper” texture often easier to detect by palpation rather than observation frequently on sun-exposed areas face, head, neck, dorsal hands, ears Evaluation Skin biopsy dysplastic epidermis with keratinocyte atypia hyperkeratotic cell with lower epithelial cells showing loss of polarity and hyperchromatic nuclei no invasion into dermis Differential Squamous cell carcinoma Actinic cheilitis Lentigo maligna Treatment Annual follow-up for skin cancer monitoring Lifestyle modification avoid sun exposure use sunscreen Surgical liquid nitrogen (cryotherapy) = most common treatment electrodesiccation and curettage Pharmacological topical 5-fluorouracil typically reserved for those with widespread actinic keratoses Prognosis, Prevention, and Complications Prognosis typically slow-growing and persistent if untreated Prevention avoid sun exposure use sunscreen Complications risk of progression to squamous cell carcinoma