Epidermal naevus is a congenital malformation of the epidermis, clinically manifested by verrucoid scaly pla-ques, often in a linear distribution following the Blaschko lines. It is considered a genetic cutaneous manifestation of mosaicism and may show different histological featu-res. Hyperkeratosis, papillomatosis and acanthosis with elongation of rete ridges is the most common pattern in epidermal naevus. However, other different histopatho-logical patterns, such as acrokeratosis verruciformis-like, epidermolytic hyperkeratosis, seborrhoeic keratosis-like, psoriasiform and acantholytic dyskeratosis have been reported occasionally (1).In addition, some authors also include a few peculiar entities showing distinctive clinical and histological fea-tures, such as inflammatory linear verrucous epidermal naevus (ILVEN), porokeratosis-like epidermal naevus, and naevus comedonicus in the spectrum of epidermal naevus (1, 2). We report here a congenital, solitary linear verrucous lesion, histologically showing epidermal hyperplasia and dilated acrosyringea filled with orthokeratotic plugs. This peculiar “epidermal naevus associated with acrosyringeal changes” seems to represent an additional histopathological variant that has received little atten-tion in the literature. CASE REPORTA 21-day-old girl was referred to our department for the evaluation of a solitary linear plaque on the right wrist that was present at birth. She was the full-term daughter of a healthy 38-year-old woman. The pregnancy had been complicated by diabetes during the last 3 months and had been treated with insulin. A caesarean section was performed because the labour was not progressing. No history of previous local trauma was recorded. There was no family history of similar dermatosis or other hereditary conditions.Physical examination disclosed a brownish, flesh-coloured, slightly verrucoid, well-demarcated plaque, 20×10 mm in diameter, on the outer aspect of the right wrist (Fig. 1). No similar lesions were noted elsewhere. The rest of the physical examination was unremarkable. Two different 4-mm punch biopsies were carried out. Histopathological examination disclosed a diffuse epi-dermal hyperplasia with basket-weave hyperkeratosis and discrete hypergranulosis. Several epidermal invagi-nations corresponding to dilated deep acrosyringea with prominent hyperkeratosis and acanthosis were noted. Orthokeratotic keratin plugs extended from hyperplasic acrosyringea to the underlying dermal eccrine ducts (Fig. 2A). Dilated eccrine ducts in the dermis under-neath epidermal invaginations were also observed (Fig. 2B). Neither loss of granular cell layer at the base of epidermal invagination or cornoid lamellae formation were observed. After multiple sections in both biopsy specimens, no evidence of parakeratotic columns within the epidermal invaginations could be demonstrated. Im-munohistochemical staining for CEA, AE1-AE3, and αEβ7 antibodies confirmed that the epidermal invagi-nations corresponded to dilated acrosyringea connected with the underlying glandular sweat ducts (Fig. 2C). DISCUSSIONWe report here an unusual solitary linear congenital hamartomatous verrucous lesion, clinically identical to an epidermal naevus, characterized histologically by an epidermal hyperplasia, dilated acrosyringea fil-led with orthokeratotic plugs without cornoid lamella formation.After reviewing the literature, we have found only one previous report showing a similar clinicopathological picture. In 1983, Imai & Nitto (3) reported a 22-year-old woman with several acquired papular lesions on the extensor aspect of her left leg under the term “eccrine nevus with epidermal changes”. Histopathological examination disclosed acanthosis, hyperkeratosis, a serrate configuration and elongation of the rete ridges. A malformed eccrine sweat structure with ductal hy-perplasia was noted.
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Aug 1, 2022
Leila Youssefian + 13
Open Access