Extragenital lichen sclerosus et atrophicus co-exististing with pemphigus vulgaris.

Sir,

Extragenital lichen sclerosus et atrophicus (LSA) is a chronic condition seen mainly on the neck, back, and upper arms. Pemphigus vulgaris is an immunobullous disorder affecting the skin mediated by auto-antibodies. Co-existence of pemphigus vulgaris with genital LSA has been reported once previously,[1] and we report this phenomenon in its extragenital variant.

A 65-year-old woman presented with multiple painful raw areas with whitish scars around them on the upper back since 2 months. The raw areas were gradually progressing. On enquiry, the patient reported that asymptomatic marks were present on the back in the same location since 6 months and flaccid blisters later developed, which left behind painful erosions. On clinical examination there were multiple erosions, a few of which were crusted, surrounded by de-pigmented atrophic plaques on the upper back [Figure 1]. A few plaques were also present in noneroded skin. Similar lesions were not present on genital or oral mucosa and scalp.

Figure 1

Crusted erosions with shiny depigmented macules on the upper back

Histopathological examination of the lesions revealed an intraepidermal suprabasal split of epidermis with intact basal keratinocytes on basement membrane in a “row of tombstone pattern.” Beneath this was a thick pale zone of papillary dermal edema separating it from dense lymphocytic lichenoid infiltrate. The collagen of reticular dermis was somewhat thicker [Figures 2 and 3].

Figure 2

Intraepidermal suprabasal blister with row of tombstone pattern of basal cells (H and E, ×10)

Figure 3

Broad zone of edema in papillary dermis with lichenoid infiltrate and thicker collagen in the reticular dermis (H and E, ×10)

Direct immunofluorescence study of noneroded skin revealed the classical fish-net pattern of fluorescence in the epidermis [Figure 4]. Anti-desmoglein (dsg) 1 and 3 auto-antibodies were present in the peripheral blood (EIA method), dsg 3 antibody level was 84.8 U/mL and dsg 1 antibody level was 23.4 U/mL (Negative: <14; Positive: >20; Indeterminate: 14–20). A final diagnosis of extragenital lichen sclerosus with pemphigus vulgaris was kept. The patient was started on azathioprine 50 mg once a day and topical high-potency corticosteroids after complete hemogram and baseline liver function tests. However, the patient was lost to follow-up.

Figure 4

Direct immunofluorescence showing fish net pattern in the epidermis (fluorescein stain ×10)

Lichen sclerosus et atrophicus (LSA) is a rare, chronic inflammatory dermatoses that affects both the dermis and epidermis.[1] Although the etiopathogenesis is not exactly known, Borreliainfections, hepatitis C infections, genetic factors, and androgen level irregularities are thought to be related.[2]

Although it is commonly seen in the anogenital area (83%–98%), it can be seen in extragenital areas in 15%–20% of patients.[3] Extragenital LSA is most commonly located on the neck, upper arms, and flexor surfaces of the wrist.[4] On histopathology LSA is classically characterized by an interface dermatitis with hyperkeratosis and follicular plugging. The zone of papillary dermal edema separates the epidermis from mixed lichenoid infiltrate.[5] In our case all these histopathological features were present along with those of pemphigus vulgaris.

Bullous variant of LSA is seen on biopsy as subepidermal blister with a broad zone of edema and greater vacuolar degeneration of basal cells.[6] In our case the blister was intraepidermal, suprabasal with acantholysis. Suprabasal clefts as an artifact of processing is not likely as the similar pattern was seen in repeated step sections and one more repeat biopsy. Also, the positive results of both DIF and dsg3 favor the diagnosis of pemphigus vulgaris.

There are many autoimmune disorders associated with LSA, such as diabetes mellitus, vitiligo, thyroiditis, and alopecia areata.[7] The phenomenon of pemphigus vulgaris occurring in the lesions of LSA cannot be explained completely, however here too, the same pathomechanism would have been operative as it is in association of LSA with other autoimmune disorders.

Circulating IgG autoantibodies targeting extracellular matrix 1 (ECM1) protein have been demonstrated in the sera of 74% of women with anogenital LSA compared with 7% in controls. The pathological changes in lesions of LSA may lead to previously sequestered site-specific skin epitopes being revealed and that those patients with an autoimmune diathesis would subsequently be more likely to develop antibodies. ECM1 autoimmunity might be an epiphenomenon rather than being directly pathogenic. Antibodies targeting the basement membrane zone (BMZ) [BP180 and BP230] have been found in one-third of patients with vulval LSA.[7]

However on literature search, no reports were found identifying the presence of epidermal intercellular autoantibodies in LSA. We propose that similar mechanism comprising of altered antigen expression and epitope spread may be at work in our case leading to blister formation.

Till date there is only one previous case series by Walsh et al.[1] describing the occurrence of immunobullous disease in genital LSA. No reports were found describing such a change in lesions of extragenital LSA, hence we report this occurrence.

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Conflicts of interest

There are no conflicts of interest.