[Vulvar lichen sclerosus. The importance of early clinical and histological diagnosis].

Vulvar lichen sclerosus (LS) is a chronic progressive skin disease of unclear etiology. It is often overlooked in early stages, but progresses to destructive atrophy and is associated with an increased risk of vulvar squamous cell carcinoma. The classical symptoms are pruritus and pain, but they are often not distinctive, so that unclear vulvar problems often lead to a biopsy. The histological picture of early LS is quite different from that of late LS with an atrophic epidermis, markedly sclerotic dermis and stiff dilated vessels. The epidermis in early LS is usually normal with only minor irregularities in the rete pattern. The basement membrane is normal or focally widened, while the edematous dermis has only scattered ectatic vessels. The often dense lichenoid and intraepidermal infiltrate explains the spongiosis and vacuolization of the basal layer keratinocytes. Very early cases may only have a sparse lymphocytic infiltrate and hyper-/parakeratosis of the follicular ostia. Early topical therapy can dampen the progression to atrophic, irreversible LS.