Genital lichen sclerosus in women is a clinically and histologically well defined disease. In addition to the classical atrophic form, there is a hypertrophic variant, which is characterised histologically by squamous cell hyperplasia. The aetiology is unknown but an autoimmune pathogenesis seems most likely. Infectious or hormonal influences do not play a major role. We describe a squamous cell carcinoma of the vulva with a co-existing lichen sclerosus. This case raises again the question of a precancerous potential of lichen sclerosus. In the dermatological literature, only a few cases with association of lichen sclerosus and squamous cell carcinoma are known. This is in contrast to gynaecological literature, where a high number of squamous cell carcinomas has been described. Gynaecologists search for the histological findings of lichen sclerosus adjacent to squamous cell carcinoma. Such an attempt is not valid without the clinical signs of lichen sclerosus, so that indeed classical lichen sclerosus does not seem to be a precancerous lesion. On the other hand, the hypertrophic form of lichen sclerosus seems to be associated with squamous cell carcinoma in about 3-5% of case.