Dermatology 1. Actinic keratosis Devan Rooney most common precancerous skin lesion in light skinned patients, more common in patients 50 years or older (most common in Celtic, Irish, and Scottish descent) Found in sun exposed areas Caused by skin cells that accumulate from repeated sun exposure Pathophys: continued sun damage from UV radiation damages the DNA in epithelial cells Primary lesions: macules or plaques, poorly circumscribed Secondary lesion: erythematous and scaly (May feel ...