Overview FreckleCaused by normal number of melanocytes but increased melanin within basal keratinocytesDarkens with sun exposureLentigoPigmented macule caused by melanocyte hyperplasiaDoes not darken with sun exposureCommon moleA benign tumor derived from melanocytesBlue nevusForm of common mole, a benign tumor derived from melanocytesBlack and blue nodule usually present at birthOften mistaken for melanomaSpitz nevusForm of common mole, a benign tumor derived from melanocytesRed-pink noduleOften seen in childrenConfused with hemangiomaDysplastic nevusAtypical, irregularly pigmented lesionIncreased risk of transformation into malignant melanomaDysplastic nevus synromeAutosomal dominant inherited diseaseMelasmaMask-like hyperpigmentation seen in pregnancy on the faceSunlight accentuates, soavoid sunlightTreat with hydroquinone creamUsually fades postpartumXanthomaYellowish papulesOften accumulations of histiocytesCan be idiopathic or associated with hyperlipidemiaCalled xanthelasma when on eyelidsTreat by decreasing lipidemiaSurgically excise as neededAcanthosis nigricansBlack, velvety plaques on flexor surfacesSeen in obesity and endocrine disorders, namely insulin resistanceCan mark underlying malignancySeborrheic keratosisBlack or brown benign plaquesAppear to be stuck on skin"Coin lesions"Commonly seen in the elderlyRuns in familiesCan be mistaken for melanomaLiquid nitrogen freezing, if not too many