Porokeratotic eccrine ostial and dermal duct nevus in Adult
Although considered a sporadic disorder, familial cases of PEODDN have been reported. Mutations in GJB2 (connexin 26) have been proven as causative via epidermal hyperproliferation owing to aberrant calcium metabolism. PEODDN also occurs in patients with Keratitis-ichthyosis-deafness (KID) syndrome (also caused by connexin 26 mutations). As with other mosaic conditions, the existence of a PEODDN may confer increased risk of transmitting a connexin mutation causing KID syndrome in offspring.
PEODDN typically appears within the first few years of life and is asymptomatic, although pruritus has been reported. Classically, it is described as linearly distributed keratotic papules and plaques with a comedo-like appearance. Verrucous lesions may also be observed. These eccrine hamartomas are most often found on the extremities, the palms and soles being most common. Rare cases also feature concurrent verruciform xanthomas or ipsilateral calcinosis. Extensive lesions may be associated with musculoskeletal anomalies such as limb shortening.
Squamous cell carcinoma arising within PEODDN has been reported, and thus clinical follow up is advisable. There are reports of PEODDN in patients with hearing loss, neurologic, and endocrine abnormalities.
D23.9 – Other benign neoplasm of skin, unspecified
239118007 – Porokeratotic eccrine ostial and dermal duct nevus
- Nevus comedonicus – Can have similar linear presentation with comedone-like structures, but histology will not show coronoid lamella.
- Porokeratotic dermatoses (punctate porokeratosis, linear porokeratosis, and porokeratosis of Mibelli) – All of these conditions demonstrate coronoid lamella on histology; however, only PEODDN will have this isolated to the acrosyringium.
- Epidermal nevus (including verrucous) – Can have linear or verrucous appearance, as has been reported with PEODDN, but histology will lack coronoid lamella.
- Inflammatory linear verrucous epidermal nevus (ILVEN) – Appearance can be linear, similar to PEODDN, but ILVEN is frequently symptomatic and clinically appears more inflammatory. Histology is confirmatory.
- Lichen striatus – Presents with hyperkeratotic papules in a linear array when extending onto the acral surfaces; histology is distinctive.
- Linear psoriasis – Clinically mimics PEODDN; a biopsy will distinguish the lesions.
- Linear lichen planus – Hypertrophic forms can mimic PEODDN; histology will differentiate these diagnoses.