Annular atrophic lichen planus associated with hypertrophic lichen planus

Abstract

Conflict of interest: none declared. We report an unusual case of annular atrophic lichen planus (AALP) associated with hypertrophic lichen planus (HLP). A 77‐year‐old man presented with several hyperkeratotic violaceous plaques and annular atrophic pigmented patches with a raised border over the left pelvic area (Fig. 1a,b). The lesions had developed simultaneously 3 years previously. There was no relevant personal or family history, and laboratory examinations were normal. A biopsy was taken, including a hyperkeratotic plaque, atrophic patch, raised border and normal skin (Fig. 2a,b). Histopathological examination of the hyperkeratotic plaque showed marked hyperkeratosis, irregular acanthosis, wedge‐shaped hypergranulosis and damage to the basal layer in the epidermis with band‐like lymphocytic infiltration in the dermis, findings consistent with HLP (Fig. 2c). On the atrophic patch, flattening of the epidermis was seen, with loss of rete ridges and fibrotic changes in the dermis (Fig. 2d). The transitional zone from the atrophic patch to the raised border showed increased cellular infiltration compared with the centre the patch (Fig. 2e). Elastic stain revealed decreased elastic fibres in the upper dermis of the atrophic lesions. When compared with normal tissues (Fig. 2f) under an electron microscope, the atrophic lesions presented deterioration of elastic fibres due to elastolysis in the upper reticular dermis, which is the characteristic finding of AALP (Fig. 2g).1–6 From these histological and electron microscopy findings, we diagnosed this case as AALP associated with HLP.