Pattern
is characterised by:
-Epidermal hyperplasia
-Elongation of rete ridges
-Thickening, clubbing and fusing of rete ridges
-Thinning of suprapapillary plate
-"Sqirting dermal papillae"
- Inflammatory cells in the epidermis
-Parakeratotic hyperkeratosis
Examples:
-Psoriasis:
-Pustular psoriasis:
-Reiter's disease:
-Clear cell acanthoma:
-Lichen Simplex chronicus:
-Chronic eczematous dermatitis: In Chronic eczematous dematitis there is
spongiosis (unlike psoriasis).
-Pityriasis rubra pilaris: Alternate vertical and horizontal
hyperkeratosis and parakeratosis is characteristic of pityriasis rubra
pilaris.
-Mycosis fungoides:
-Fungal infection:
-Bowen's disease (psoriasiform variant):