Skin histopathology

Question 1

What type of histological pattern is oczema

Answer 1

spongiotic

Question 2

What is the commonest type of lichen inflammation

Answer 2

lichen planus

Question 3

Psoriasiform reaction example

Answer 3

psoriasis

Question 4

what is the reaction pattern of psoriasiform

Answer 4

extensor surfaces

Question 5

What is the pathophysiology of psoriasiform reactions

Answer 5

 Normal keratinocyte turnover time = 56 days
 Psoriasis keratinocyte turnover time = 7 days
 Rapid turnover  epidermis thicker
 A layer of parakeratosis forms at the top
 Stratum granulosum disappears as not enough time to form it; and dilated vessels form
 Munro’s microabscesses form, made up from recruitment of neutrophils

Question 6

vesicobullous /bullous pemphigoid pathophysiology

Answer 6

 IgG and C3 attack the basement membrane
• Detected by immunofluorescence
• IgG anti-hemidesmosome

Question 7

presentation of bullous pemphigoid

Answer 7

o Elderly, autoimmune, high mortality rate (10-20%)
o Flexor surfaces, tense bullae
 Dermo-epidermal junction affected

Question 8

pemphigus vulgaris pathophysiology

Answer 8

o Flaccid blisters, rupture easily
 Epiderma-epidermal junction affected
o Pathophysiology:
 IgG attacks between the keratin layers (acantholysis)
• I.E. Loss of intracellular connections
• Top epidermis sloughs off
 Common for many conditions;

Question 9

Seborraic keratosis appearance and pathophysiology

Answer 9

Cauliflower”, pigmented, gets caught on clothing (and taken off)
o Stuck-on appearance, harmless and benign
o Histopathology:
 Lots of growth and ordered proliferation
 Ordered and benign growth
 “Horn cysts” – epidermis entrapping keratin

Question 10

BCC appearance and pathophysiology

Answer 10

o Rolled, pearly-edge, central ulcer, telangiectasia
 “Rodent ulcer” as it burrows away
o Benign but can disfigure
o Occurs in sun-exposed areas
o Histopathology:
 Dysplastic change
 Cancer from keratinocytes at bottom of epidermis
 Cannot break through the BM  cannot metastasise

Question 11

Mutation in BCC

Answer 11

PTCH mutation

Question 12

Squamous cell carcinoma appearance and pathophysiology

Answer 12

o Subdivided into level of differentiation:
 Poorly to well differentiated
o Poorly differentiated means you cannot determine origin cell lineage
o Peri-neural invasion can occur (i.e. local invasion)
looks pink under microscope, keratin pearl

Question 13

Gorlins syndrome

Answer 13

mutation in PTCH1 leads to increase in risk of BCC development

Question 14

Bowen’s disease

Answer 14

o Squamous cell carcinoma in situ [i.e. pre-cancerous]
o Keratinocytes become more pleiomorphic and larger with mitotic figures
o Bowen’s disease name changes depending on location (i.e. anal vs. cervix)

o Dysplasia can be 1, 2 or 3 (low, moderate or high grade)`

Question 15

What is pagetoid spread

Answer 15

ascent of melanocytes in melanoma

Question 16

appearance of melanoma

Answer 16

o	Irregular border							
o	Variable pigmentation						 
o	Bleeding
o	Itchy
o	Growing

Question 17

appearance of melanoma under the microscope

Answer 17

blue, highly mitotic,

Question 18

Breslow thickness

Answer 18

thickness of 4mm or above = high mortality 50% (blood vessels -> highly metastasisable)

Question 19

what is the significance of the BRAF V600 mutation

Answer 19

can receive targeted therapy

Question 20

layers of skin

Answer 20

stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale, melanocytes, basement membrane, dermis, then subcutaneous fat

Question 21

how thick is the epidermis, dermis and subcutaneous fat together

Answer 21

6mm

Question 22

what is the dermis made of

Answer 22

blood vessels, sweat glands, fair follicles, sebaceous glands and nerve fibres