Porokeratotic Eccrine Nevus Research Articles

Keratitis-ichthyosis-deafness syndrome with GJB2 mutation manifesting generalized erythematous plaques of porokeratotic eccrine ostial and dermal duct nevus

Porokeratotic eccrine ostial and dermal duct nevus or porokeratotic eccrine nevus (PEN) is a rare nevoid condition characterized by asymptomatic spiny, keratotic papules, and plaques in linear distribution along Blaschko's lines on the extremities clinically and discrete vertical cornoid lamellae at eccrine ostia pathologically. Keratitis–ichthyosis–deafness (KID) syndrome manifests generalized erythematous plaques with tiny papules and keratotic spicules. Both rare diseases are associated with mutations of the GJB2 gene encoding for gap junction protein, connexin 26. We present a case of KID syndrome in an 11-year-old boy. The patient presented with bilateral hearing loss, and large erythematous plaques with grained leather-like appearance and occasional keratotic spicules on the face and trunk as well as prominent hyperkeratosis on the acral parts, especially distal digits. Skin biopsy of two skin lesions revealed features of PEN. Mutation analysis of peripheral blood revealed GJB2 c. 263C>T (p.A88V). This is the first report of GJB2 gene mutation in a Taiwanese boy with KID syndrome. The histologic features of PEN in the present case provide additional support that PEN may be part of the manifestation of KID syndrome.

Porokeratotic eccrine nevus

Porokeratotic eccrine nevus

Porokeratotic Eccrine Nevus May Be Caused by Somatic Connexin26 Mutations

Porokeratotic eccrine ostial and dermal duct nevus, or porokeratotic eccrine nevus (PEN), is a hyperkeratotic epidermal nevus. Several cases of widespread involvement have been reported, including one in association with the keratitis–ichthyosis–deafness (KID) syndrome (OMIM #148210), a rare disorder caused by mutations in the GJB2 gene coding for the gap junction protein connexin26 (Cx26). The molecular cause is, as yet, unknown. We have noted that PEN histopathology is shared by KID. The clinical appearance of PEN can resemble that of KID syndrome. Furthermore, a recent report of cutaneous mosaicism for a GJB2 mutation associated with KID describes linear hyperkeratotic skin lesions that might be consistent with PEN. From this, we hypothesized that PEN might be caused by Cx26 mutations associated with KID or similar gap junction disorders. Thus, we analyzed the GJB2 gene in skin samples from two patients referred with generalized PEN. In both, we found GJB2 mutations in the PEN lesions but not in unaffected skin or peripheral blood. One mutation was already known to cause the KID syndrome, and the other had not been previously associated with skin symptoms. We provide extensive functional data to support its pathogenicity. We conclude that PEN may be caused by mosaic GJB2 mutations.

Trichilemmal cyst nevus: A new complex organoid epidermal nevus

A 31-year-old woman had an organoid nevus characterized by multiple trichilemmal cysts arranged in a bandlike pattern. The involved streaks followed Blaschko's lines and were covered, in addition, by multiple filiform hyperkeratoses and comedo-like plugs. Some histopathologic features of this complex nevus were reminiscent of those of well-established organoid nevi such as nevus comedonicus, porokeratotic eccrine nevus, or hair follicle nevus, but the presence of multiple large trichilemmal cysts was a conspicuously distinctive abnormality. Consequently, we propose for this new organoid nevus the names "trichilemmal cyst nevus" or "nevus trichilemmocysticus."