Histological examination on the epidermis showed extensive multifocal areas of ortho and hyperkeratosis, and parakeratotic
pseudoepitheliomatous hyperplasia and acanthosis (Figure 2D) with intracorneal microabscesses and presence of basophilic filamentous structures that were morphologically consistent with D.
The epidermis in dVIN is usually thickened and hyperkeratotic and/or parakeratotic
with elongated and anastomosing rete ridges.
Porokeratosis (PK), first described in 1983, is a chronic parakeratotic
A prominent parakeratotic
column within an epidermal invagination that displays loss of the granular layer is found overlaying an eccrine duct with a dilated acrosyringium.
Porokeratosis is a specific keratinization disorder that manifests clinically as well-demarcated annular or linear keratotic plaques of various sizes and forms and with distinguished histology showing cornoid lamella, which is a column of closely packed parakeratotic
cells extending through the stratum corneum.
It is characterised clinically by hyperkeratotic papules or plaques with raised and advancing edge, which histologically corresponds to a column of parakeratotic
The scutula are masses of keratinised as well as parakeratotic
cells, exudate and inflammatory cells intermingled with hyphae and spores.
The luminal surface has flattened, parakeratotic
epithelial cells exhibiting a corrugated appearance.
Microscopic examination revealed hyperplastic parakeratotic
stratified squamous epithelium of variable thickness (Figure 3).
There is a very distinctive and characteristic wavy or corrugated, refractile keratinization at the luminal surface, often as sociated with parakeratotic
epithelial cells (figure 2).
The affected keratinocytes fail to undergo normal keratinisation and are pushed upwards to form a compact parakeratotic
layer beneath the previously normal orthokeratotic stratum corneum.
Biopsies of the hyperpigmented areas revealed an acanthotic, parakeratotic
and hyperkeratotic squamous epithelium with hyperpigmentation of the basal layer of the epithelium with increased number of melanocytes (Fig.