Early vulvar lichen sclerosus: a histopathological challenge

Vulvar lichen sclerosus (LS), a lymphocyte-mediated chronic skin disease, begins with uncharacteristic symptoms and progresses undiagnosed to atrophy and destructive scarring. Some patients with longstanding advanced LS have an increased risk of vulvar carcinoma. Early LS is treatable, although not curable, if diagnosed early. Therefore, patients with persistent vulvar symptoms should be biopsied to establish the diagnosis. In contrast to advanced LS, the histological features in early LS are quite subtle and often more prominent in adnexal structures than in interfollicular skin. Adnexal structures show acanthosis, luminal hyperkeratosis and hypergranulosis with/without dystrophic hair and basement membrane thickening. The epidermis/mucosa shows mild irregular, occasionally psoriasiform acanthosis and focal basement membrane thickening. Early dermal changes are homogenized collagen and wide ectatic capillaries in dermal papillae immediately beneath the basement membrane. The lymphocytic infiltrate can be sparse or dense, lichenoid or interstitial with epidermal lymphocyte exocytosis and lymphocytic/lymphohistiocytic vasculitis. Dermal melanophages indicate preceding keratinocyte/melanocyte destruction. Biopsy specimens of early LS rarely display all features. Therefore, serial sections and periodic acid-Schiff reactions are necessary for their identification. Recognition and treatment of these early stages of LS may result in longstanding remission. Progression to atrophic stages with their associated morbidity and even to squamous cell carcinoma may be prevented.