Snapshot A 66-year-old man comes to his primary care physician concerned about melanoma. He notes that over the past several years, several greasy moles have cropped up on his back. His cousin had died of melanoma and he is scared that these moles are melanomas. On exam, the moles appeared flat, greasy, and dark with a “stuck on” appearance. He is reassured that these are not melanomas and do not have malignancy potential. Introduction Common, benign persistent epidermal proliferations with variable appearances Can mimic malignancies, especially melanoma Genetics can be inherited Epidemiology rare before 30-years-old one of the most common benign growths Associated conditions underlying GI or lymphyoid malignancies Leser-Trélat sign: sudden appearance of multiple seborrheic keratoses may indicate underlying malignancy NOT related to actinic keratosis or seborrheic dermatitis (despite the similarity in name) Presentation Symptoms asymptomatic patients can often scratch off a lesion Physical exam usually multiple lesions typically at any site except lips, palms, soles common on trunk, face, extremities variable appearance flat or raised smooth, velvety, or verrucous color ranges from white, pink, brown, or black even within a single lesion, color may vary “stuck on” waxy, greasy appearance inflammed seborrheic keratoses may have edema, erythema, hemorrhage Evaluation If clinically mimicking skin cancer (e.g., with very dark pigmentation suspicious of melanoma) skin biopsy Differential Melanoma can be mistaken for melanoma Treatment Typically not treated unless for cosmetic reasons for flat lesions, liquid nitrogen (cryotherapy) for raised lesions, curettage Prognosis, Prevention, and Complications Prognosis persistent, grows slowly no risk for progression to malignancies