Lichen sclerosus and lichen planus: a spectrum of disease? Report of two cases and review of the literature.

There has long been controversy concerning the relationship between lichen planus and lichen sclerosus. Whilst these two conditions are now considered distinct, there are shared clinical and pathological features. We now describe two patients with the cutaneous involvement of both lichen planus and lichen sclerosus, presenting a review of similar reported cases and discussing the implications for pathogenesis of these two diseases. Neither lichen planus (LP) nor lichen sclerosus (LS) are uncommon yet they have only infrequently been reported as coexisting. In his original description of LS, however, Hallopeau considered it to be a variant of LP and Gougerot has also commented on a possible common pathogenesis for the two conditions. Features which tend to support such as association include the distribution of the cutaneous lesions, histopathological features such as hydropic basal cell degeneration and a band-like lymphohistiocytic infiltrate in the dermis, and the reported association with autoimmune disease. We now report two patients in whom coexistent cutaneous LS and LP was confirmed histologically.