A case of simultaneously occurring lichen sclerosus and segmental vitiligo: connecting the underlying autoimmune pathogenesis

A 41‐year‐old African‐American woman reported a 6‐month history of asymptomatic white macules and patches that started on her left foot, and then spread proximally up her leg to her thigh, and then to her buttocks. She also noted that several of her pubic hairs had turned white, but only on the left side of the midline. She also complained of concomitant severe burning and itching in the vaginal area and that her vaginal skin had turned whitish pink. The patient denied contact with industrial or hazardous chemicals, and her medical history included childhood iron deficiency anemia only. On examination, the patient had linear guttate hypo‐ and depigmented macules on the left dorsal foot, extending up the medial calf, the medial and posterior thigh, and coalescing into scalloped patches across her left medial buttock (Fig. 1). There was sharp midline demarcation in the suprapubic region. Her pubic hairs on the left side were predominantly depigmented. Examination of the genital area revealed areas of atrophy, together with slightly hyperkeratotic pink and hypopigmented plaques covering the entire perineal area, with a slightly irregular rim of gray–brown hyperpigmentation almost encircling the introitus. The lichen sclerosus of the labia minora extended directly into the perianal region (Fig. 2). The vulvar area was tender to the touch. 1 Hypo‐ and depigmented macules and patches on the medial left calf, thigh, and pubic area 2 Depigmented pubic hair on the left side and pink–white sclerotic plaques in the perineal area A punch biopsy specimen taken from the perineum adjacent to the introitus showed a lichenoid infiltrate and papillary dermal sclerosis that was compatible with lichen sclerosus (Fig. 3). A Fontana–Masson stain showed complete absence of melanin in the epidermis, but melanophages were found in the dermis and in the lichenoid inflammatory infiltrate (Fig. 4). Melanin was also absent from the follicular epithelium of a hair follicle, but was present in the hair shaft of that follicle. Based on the clinical presentation and histology, a diagnosis was made of segmental vitiligo of the left lower extremity with overlapping lichen sclerosus in the perineal region. 3 Histology shows hyperkeratosis, epidermal atrophy, and a lichenoid infiltrate with papillary dermal sclerosis (hematoxylin and eosin stain, ×4) 4 Complete absence of melanocytes demonstrated in the epidermis (Fontana–Masson stain, ×10) On two follow‐up evaluations spanning 6 weeks aft