A case of cutaneous lichen sclerosus et atrophicus effectively treated by extracorporeal photochemotherapy.

Lichen sclerosus et atrophicus (LSA) is an inflammatory disease that affects the genitals, which was first described by Hallopeau in 1887 and is of unknown etiology. Only 15% of patients have an associated extra-genital form, and 2.5% have an isolated extra-genital form. LSA treatment remains poorly codified and mostly empirical. Here, we report a case of LSA, of mainly cutaneous form, which was effectively treated using extracorporeal photochemotherapy (ECP). Remission was achieved quickly, after the fourth session, with excellent treatment tolerance. ECP is now recognized as an effective treatment for erosive lichen planus, graft-versus-host disease (GVHD), and scleroderma. Thus, we began ECP treatment for our cases of LSA based on clinical and/or anatomopathological similarities between LSA and these commonly ECP-treated disorders. The fact that ECP is effective in LSA, GVHD, erosive lichen planus, and scleroderma strengthen the hypothesis that there is a common link between these four conditions.