[Squamous epithelial cancer in lichen ruber hypertrophicus--a case report with a review of the literature].

Spinocellular carcinoma developed in a 19-year-old lesion of lichen ruber hypertrophicus of the lower leg. In the literature,24 cases of spinocellular carcinoma in lesions of cutaneous lichen ruber have been reported. X-ray and arsenic treatment has often preceded malignant transformation. Another risk factor seems to be the chronic hypertrophic type of lichen ruber located on the lower extremities.