Bilateral zosteriform extragenital lichen sclerosus.

A 35-year-old man presented with asymptomatic eruption on both forearms and lower aspects of the legs for 6 months. The lesions first appeared on his inner aspects of the wrist, the dorsal surface of the hands, and legs and progressed to involve proximal aspects of the extremities. There was no significant past history. On examination, multiple pearly white papules and depigmented atrophic plaques were found bilaterally on the flexors of the arms and the extensors of the legs. The lesions were arranged in a linear manner, following the lines of Blaschko (Figures 1 and 2). The surface of the atrophic plaques was notable for prominent telangiectasia, giving an erythematous appearance. The genitalia, oral cavity, palms, and soles were spared. Systemic examination was noncontributory. Lichen striatus and extragenital lichen sclerosus (ELS) were considered the differential diagnosis. Clinically, the age of the patient, the absence of scaling, and the presence of atrophic plaques and telangiectasia were in favor of ELS. A punch biopsy from an atrophic plaque was performed, and it revealed hyperkeratosis, atrophic epidermis, basal layer vacuolar degeneration, mild lymphocytic infiltration in the dermis, edema, and homogenization of collagen of the upper portion of the dermis (Figures 3 and Figure 4). Histopathologic findings were consistent with lichen sclerosus. A diagnosis of bilateral zosteriform ELS was made.