Disscusion

EN is fundamentally a hamartoma of keratinocytes and occasionally adnexal structures. It mostly develops in the first years of life, although late-onset presentation has also been reported ¹´⁴. Martinez et al report a 27 years old woman who developed EN during pregnancy. They proposed hormonal and immunological alternations during pregnancy as a possible explanation ⁵.
More than 10 histopathological variants of EN have been described so far and papillomatosis, hyperkeratosis, and acanthosis are the most common findings. Epidermolytic hyperkeratosis is an uncommon variant ⁶.
Epidermolytic hyperkeratosis is characterized by granular and vacuolar degeneration of keratinocytes in the spinous and granular layer of epidermis along with hyperkeratosis. In addition to EN, this histological pattern can be seen in epidermolytic ichthyosis, specific kinds of palmoplantar keratodermas and epidermolytic acanthoma ⁷.
The dermoscopy view of the epidermolytic hyperkeratosis EN is mostly similar to other kinds of EN containing: large brown circles and the absence of the pigment network ²´⁸. Carbotti et al first described large brown circles in EN and correlated it histologically to the way pigmented keratinocytes lie down around dermal papillae ². Demographics and dermoscopic features of epidermolytic hyperkeratosis EN being reported in the literature are summarized in Table 1.
The clinical differential diagnosis of this lesion includes wart and seborrheic keratosis which can be excluded by considering the unique clinical pattern of EN (blaschkoid distribution) and lack of cytopathic viral effects, which are seen in the wart.
Full-thickness surgical excision is the treatment, but in large lesions hypertrophic scar and keloid formation is the side effect. Other treatment modalities include electrofulguration, cryosurgery, and dermabrasion, but they make scarring. Topical agents (calcipotriol, steroids, retinoic acid) were not effective. Soft and flat nevi were responsive to ablative lasers, but the lesions may recur after non-surgical procedures. So because of the side effects of extensive surgery a conservative approach is logic in the case of extensive lesions9.
In conclusion epidermolytic hyperkeratotic EN is a rare variant of EN, which can be congenital or developed later in adulthood. Although the histopathological finding of this variant is unique and is different from other variants of EN, the dermoscopic feature is the same and can be considered an important clue in the diagnosis of different variants of EN.