Squamous cell carcinoma arising in hypertrophic lichen planus.

Hypertrophic lichen planus (HLP) is a chronic T-cell-mediated inflammatory disease characterised by pruritic hypertrophic or verrucous plaques on the lower limbs. We report a case of an 87-year-old woman with a 12-year history of HLP on both lower legs presenting with malignant transformation of one lesion into a squamous cell carcinoma (SCC). Malignancy developing in cutaneous lichen planus is rare, with less than 50 cases reported in the literature.