intraepidermal carcinoma /in′trə·ep′idur″məl/ [L, intra + Gk, epi, above, derma, skin] , a neoplasm of squamous epidermal cells that does not proliferate into the basal area and often occurs in many sites simultaneously. The lesions, which enlarge slowly, are resistant to chemotherapy and to radiation. Also called precancerous dermatitis.