Psoriasiform dermatitis

Question 1

Psoriasiform epidermal hyperplasia =

Answer 1

Acanthosis with elongation of the rete ridges

Question 2

Psoriasis

1. Histology
2. DDX

Answer 2

Histology

1. Regular acanthosis
2. Hypogranulosis
3. PK with neutropbils (Munro’s microabscesses)

(Guttate and early psoriasis have less acanthosis and more spongiosis)

DDX:

1. Pale cell acanthoma
2. Chronic spongiotic dermatitis
3. PR
4. Lichen simplex chronicus
5. Mycosis fungoides late patch/plaque stagae
6. Necrolytic migratory erythema

Question 3

Chronic spongiotic dermatitis

Histology

DDX

Answer 3

Histology

1. Irregular or uneven hyperplasia
2. PK
3. Minimal spong

DDX:

Any dermatitis in chronic phase, including tinea!

Question 4

Lichen simplex chronicus

Histology

Answer 4

Hyperkeratosis

Irregular acanthosis

Hypergranulosis

Papillary dermal fibrosis

Question 5

Mycosis fungoides late patch/plaque stage

Answer 5

Psoriasiform lichenoid pattern

Cytologic atypia

Epidermostropism

Lining up of atypical cells

Pautrier’s microabscesses

Question 6

Necrolytic migratory erythema

Histology

DDX

Answer 6

Histology

1. Pale keratinocytes
2. Superifical necrosis
3. Neutrophilic crust

DDX:

Zinc deficiency (acrodermatitis enteropathica)

Niacin deficiency (pellagra)

Psoriasis