Systematized porokeratotic eccrine and hair follicle naevus: report of a case and review of the literature

Abstract

We report a unique case of a congenital keratinocytic naevus associated with severe alopecia, onychodysplasia and palmoplantar involvement in a 13-year-old girl. The lesions, consisting of scaly, spinous and verrucous papules and plaques, mainly followed Blaschko's lines and have remained unchanged since birth. The predominant histopathological picture was that of a column of parakeratosis overlying the eccrine ostia and hair follicles. This is the first case of a systematized keratinocytic naevus characterized by histopathology of eccrine and hair follicle porokeratosis and a widespread bilateral involvement. This may be a distinct entity to be included in the differential diagnosis of linear, hyperkeratotic dermatoses. We suggest its classification as systematized porokeratotic eccrine and hair follicle naevus.

Widespread porokeratotic adnexal ostial nevus: Clinical features and proposal of a new name unifying porokeratotic eccrine ostial and dermal duct nevus and porokeratotic eccrine and hair follicle nevus

“…The distribution of PAON plaques along the lines of Blaschko lends support for the role of somatic mosaicism, reflecting clonal expression of abnormal cells derived from the neuroectoderm. 4 Rare studies have looked at potential specific defects in PEODDN, and the relationship of cornoid lamellae to adnexa. Stoof et al 10 found that only ducts within the parakeratotic column stained with carcinoembryonic antigen, whereas the outer wall of the invagination did not.…”

“…3,4 Some authors propose that PEHFN and PEODDN are variants of the same process, differentiated by the adnexal structure or structures affected and the level of involvement. 4,9 Examination of multiple level sections in our 5 cases demonstrated that 3 had involvement of both acrosyringia and acrotrichia (cases 1, 2, and 4), suggesting a more accurate diagnosis of PEHFN/PEODDN overlap. It may be that other cases of PEODDN, if examined in this way, might also demonstrate follicular involvement in nonacral lesions.…”

“…6 involving the proximal extremities, trunk, buttocks, neck, or a combination of these has been reported in 13 of 39 cases of PEODDN. 4,6,8,11,12,15,20,21,[23][24][25][26]29,31 Of the two cases of PEHFN, one had localized acral involvement 3 and the other had widespread bilateral involvement. 3,4 The clinical and histologic characteristics of our 5 cases of PAON and 13 previously reported widespread cases of PEODDN and PEHFN are summarized in Table I (available online at http://www.…”

“…There have been two prior reports of PEHFN 3,4. Of the 39 total cases of PEODDN, 2 had onset of the disease at birth,1,[5][6][7][8][9]11,13,14,16,18,21,23,24,26, 29-31,33,34,36,39,41 6 had onset in the first few years of life…”

“…1,2 The two previously reported cases of PEHFN appeared at birth and 2 years of age, respectively. 3,4 Lesions typically present as multiple asymptomatic hyperkeratotic papules and plaques as well as punctate pits, which are often filled with a comedo-like keratin plug. The most common areas of involvement are the distal extremities, although the proximal extremities, trunk, and face can also be involved.…”