Extramammary Paget's disease masquerading as lichen sclerosus

A wide range of genital infections and skin conditions may present with vulval pruritus. Lichen sclerosus is one cause. This is often associated with visible skin changes which include atrophy, resorption or fusion of the labia, sclerosis and excoriation. Ulceration may indicate malignant transformation and requires urgent biopsy. Many experienced clinicians diagnose lichen sclerosus on clinical appearance, however we recommend a low threshold for biopsy, especially for non-responding or odd looking lesions. We report a patient whose vulval skin biopsy for clinically suspected lichen sclerosus revealed extramammary Paget's disease of the vulva. We review the pathology, prognosis and treatment of this condition.