Porokeratosis
Encyclopedia
Porokeratosis is a specific disorder of keratinization that is characterized histologically by the presence of a cornoid lamella, a thin column of closely stacked, parakeratotic cells extending through the stratum corneum
with a thin or absent granular layer.
However, additional types have also been described:
Stratum corneum
The stratum corneum is the outermost layer of the epidermis, consisting of dead cells that lack nuclei and organelles. The purpose of the stratum corneum is to form a barrier to protect underlying tissue from infection, dehydration, chemicals and mechanical stress...
with a thin or absent granular layer.
Types
Porokeratosis may be divided into the following clinical types:- Classic porokeratosis Mibelli
- Disseminated superficial actinic porokeratosisDisseminated superficial actinic porokeratosisDisseminated superficial actinic porokeratosis is a non-contagious skin condition with apparent genetic origin in the SART3 gene. It most often presents in sun-exposed areas of the body. Some DSAP cases have been reported in patients with acute immune compromised situations, particularly in the...
- Disseminated superficial porokeratosisDisseminated superficial porokeratosisDisseminated superficial porokeratosis is a more generalized processes than porokeratosis Mibelli, and involves mainly the exptremities in a bilateral, symmetric fashion. In about 50% of cases, skin lesions only develop in sun-exposed areas, and this is referred to as disseminated superficial...
- Porokeratosis palmaris et plantaris disseminataPorokeratosis palmaris et plantaris disseminataPorokeratosis palmaris et plantaris disseminata is characterized by skin lesions that are superficial, small, relatively uniform, and demarcated by a distinct peripheral ridge of no more than 1mm in height....
- Linear porokeratosisLinear porokeratosisLinear porokeratosis is characterized clinically by basic skin lesions that are identical to those of classic porokeratosis Mibelli, including lichenoid papules, annular lesions, hyperkeratotic plaques with central atrophy, and the characteristic peripheral ridge....
- Punctate porokeratosisPunctate porokeratosisNot to be confused with Spiny keratoderma ...
However, additional types have also been described:
- Porokeratosis plantaris discretaPorokeratosis plantaris discretaPorokeratosis plantaris discreta is a skin condition that occurs in adults, with a 4:1 female preponderance, characterized by a sharply marginated, rubbery, wide-based papule.It is also known as "Steinberg's lesion".It was characterized in 1970....