Angiokeratoma-like changes in extragenital and genital lichen sclerosus.

Hemorrhagic blisters have rarely been described developing in the background of either genital or extragenital lichen sclerosus and have invariably been designated clinically as telangiectatic, hemorrhagic or bullous lichen sclerosus. We describe three patients with extragenital and genital lichen sclerosus, who presented clinically with hemorrhagic plaques and/or papules. In addition to the classical histology of lichen sclerosus, dilated, congested and focally thrombosed vascular channels lined by flat endothelium were seen within the sclerotic dermal collagen. They were in close proximity to and even in contact with the overlying epidermis and thus mimicked an angiokeratoma. Angiokeratoma-like changes in lichen sclerosus represent secondary features because of damage to the dermis by lichen sclerosus and are characterized histologically by ectatic thin-walled vascular spaces in the papillary dermis intimately associated with the epidermis. Increased venous pressure, local trauma, degenerative changes in the elastic tissue of the vessel wall and/or surrounding supportive tissue, as well as abnormalities in the extracellular protein network, appear to be implicated in their pathogenesis.