We report a 19-year-old man with hyperkeratosis of nipple and areola which is a part of an epidermal nevus. He did not have a history of endocrinopathy or synthetic steroid therapy. The lesion, a fingertip sized verrucous dark browncolored macule on left upper back, had spread into left-anterior chest wall and had involved nipple and areola to make them hyperkerstotic and verrueous. Histologic section from the on left areola showed hyperkeratosis, papillomatosis, acanthosis and increased pigmentation in the basal cell layer. Chernical peeling with 30% trichloroacetic showed favorable response. (Kor J Dermetol 28(l): 90 83, 1900)