“…Such factors are mentioned in many of the cases in the literature and it seems to be essential in cases of lichen planus of the mouth to remove any form of local irritation. Tliree cases have been described where epithelioma has developed on top of hypertrophic cutaneous lichen planus (Brennan and Teplitz, 1958 ;Wilson, 1953 ;Lyell and Whittle, 1951), but the trauma to these lesions must be considerable over the years. It is well recognized that there is a greater tendency for epithelioma to develop in the mouth, A number of authorities state that epithelioma can occur on top of lichen planus of the vulva.…”