Histopathology 6 - Skin pathology

Question 1

Where does the dermis sit relative to the basement membrane?

Answer 1

The dermis sits below the BM

Question 2

What features are seen in the dermis layer?

Answer 2

Blood vessels, sweat glands, hair follicles, sebaceous glands and nerve fibres

Question 3

Layers of skin “come lets get some beers”

Answer 3

Stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

Question 4

Features of palmar-plantar skin

Answer 4

No sebaceous glands, very thick corneal layer

Question 5

Name 3 vesiculobullous skin diseases

Answer 5

Bullous pemphigoiD
Pemphigus vulgariS
Pemphigus folliaceous

Question 6

Clinical features of bullous pemphigoid

Answer 6

Elderly, flexural surfaces, tense bullae

Question 7

What would be seen on immunofluorescence of patient with bullous pemphigoid?

Answer 7

IgG and C3 deposition at dermoepidermal junction

Question 8

Pathophysiology of bullous pemphigoid

Answer 8

Autoimmune disorder caused by IgG and C3 attack of the basement membrane, causes the epidermis to lift off the BM. Eosinophils also recruited which cause further damage to anchoring proteins which are anchoring the lower keratinocytes to the BM. (anti-hemidsemosome IgG)

Question 9

Clinical features of pemphigus vulgaris

Answer 9

Flaccid blisters which rupture easily

Question 10

Pemphigus vulgaris pathophysiology

Answer 10

IgG antibodies attack between the keratinocyte layers (Acantholysis) –> IgG deposits in epidermo-epidermal junction (need immunofluorescence to confirm diagnosis)

Question 11

Which is most superficial of the vesiculobullous conditions?

Answer 11

Pemphigus foliaceous

Question 12

Pemphigus foliaceous pathophysiology

Answer 12

IgG against desmoglein of the stratum corneum, v thin top layer of skin
Diagnosed with immunofluorescence

Question 13

Pattern of inflammation in eczema

Answer 13

Spongiotic as you get oedema between the keratinocytes

Question 14

Pathophysiology of psoriasis

Answer 14

Much faster turnover of keratinocytes –> thickened epidermis + layer of parakeratosis at the top

Question 15

The inflammatory cell in eczema and psoriasis, respectively

Answer 15

Eczema: eosinophils
Psoriasis: Neutrophils

Question 16

Which layer of skin disappears in psoriasis?

Answer 16

Stratum granulosum, there is not enough time for it to form

Question 17

What are Munro’s micro abscesses and what condition are they seen in’/

Answer 17

In psoriasis, neutrophil recruitment forms Munro’s micro abscesses

Question 18

Which cell mediates lichen planus?

Answer 18

T cell mediated

Question 19

How does lichen planus appear on the wrist and how does it appear in the mouth?

Answer 19

on wrist = purple/red papule and plaques

Mouth: white lines known as WICKHAM STRIAE

Question 20

Pathophysiology of lichen planus

Answer 20

T-cells have destroyed bottom keratinocytes –> band-like inflammation

Question 21

Pyoderma gangrenosum type of disease

Answer 21

Vasculitis, not gangrenous

Question 22

“stuck on” appearance + benign

Answer 22

Seborrhoeic keratosis

Question 23

What kinda cysts are seen in seborrheic keratosis

Answer 23

Keratin “horn” cysts

Question 24

Name a disease which is a pre-malignant skin neoplasm?

Answer 24

Bowen’s disease (SCC in situ)

Question 25

When Bowen’s disease invades the dermis, what is this?

Answer 25

SCC

Question 26

What causes a junctional naevus?

Answer 26

Melanocytes in the epidermis (they normally reside in the basal layer of epidermis)

Question 27

Most important prognostic factor for malignant melanoma?

Answer 27

breslow thickness

Question 28

The histopathology of melanoma, what kind of spread?

Answer 28

PAGETOID SPREAD (BAD), mitotic figures