T10-L1: Inflammatory Skin Diseases and Cancer

Question 1

What changes are seen microscopically in eczema?

Answer 1

Oedema between the keratinocytes - known as Spongiosis. There is so much oedema that vesicle form in which there are inflammatory cells. Chronically there is thickening of the epidermis and the spongiosis is less appreciable.

Question 2

What type of hypersensitivity is contact irritant dermatitis due to?

Answer 2

Type 4 Hypersentistity. common allergens include nickel, dyes, rubber etc.

Question 3

What microscopic changes do we seen psoriasis?

Answer 3

“Psorisasiform hyperplasia”

• Regular elongated club shaped retentions ridges
• Thinining of the epidermis over the dermal papillae (leading to bleeding)
• Small aggregations of acute inflammatory cells within the scale

Question 4

What is the aetiology of Psoriasis?

Answer 4

We see a family history - multiple loci in the 6p2 (MHC complex) are implicated. This area is associated with other autoimmune disorders (psoriasis may be autoimmune but the pathogenesis is not well understood) such as IBM and MS. It is associated with environmental factors such as infection, stress, trauma and drugs.

Question 5

What comorbidities are associated with psoriasis?

Answer 5

• 5-10% associated with large or small joint arthritis
• Psychosocial factors can be associated with alopecia
• CVD shows a 2-3x risk
• Increased risk of non-melanoma skin cancer and Lymphomas

Question 6

What areas does Lichen plants affect?

Answer 6

This affects the flexor surfaces, mucous membranes and genitals. It is characterised by red papules, which may be itchy. It is found generally in adults and is self-limiting but may be long term especially in the oral cavity. It is unknown aetiology but may have type 4 hypersensitivity reaction. It is associated with other diseases such as viral hepatitis, HIV and drugs.

Question 7

What level of the skin does Lichen Planus affect?

Answer 7

The Dermis - Microscopically it is characterised by a band of chronic inflammatory infiltrates (mainly lymphocytes) below the epidermis. Some may go and damage the basal layer. It is a type of interface dermatitis.

Question 8

What is DLE?

Answer 8

Discoid Lups Erythematosus - this is a form of Lupus erythematosus that affects the skin only. It leads to coin like lesions and is worse upon exposure to sunlight.

Question 9

How can we test of LE?

Answer 9

Presence of autoantibodies IgG using immunofluorescence in the basement membrane (ANA testing).

Question 10

How does dermatomyositis present?

Answer 10

This is a peri-ocular odema and erythema. There is erythema in a photosensitive distribution. Myositis: proximal muscle weakness and so can get fatigue, also can check check creatinine kinase. In adults, 25%, associated with underlying visceral cancer.

Microscopically it looks similar to lupus. You often see a lot of dermal mucin but you will not see the immunoglobin (negative IMF).

Question 11

What is the difference between Pemiphigoid and Pemphigus?

Answer 11

Pemphigoid - Tense sub-epidermal blisters

Pemphigus - Intraepidermal blisters

The are both autoimmune and so can use immunoflorence to demonstrate the presence of antibodies. In pemphigoid these antibodies are against the basement membrane compared to intracellular junctions in pemphigus.

Question 12

Which group of disorders is characterised by the loss of cohesion between keratinocytes, forming fragile bullae that rupture easily?

Answer 12

Pemphigus - in pemphigoid the bull are tense and do not rupture easily. The epidermis lists away from the underlying dermis.

Question 13

What skin disease is associated with young patients and coeliac disease?

Answer 13

Dermatitis herpetiformis

Question 14

What skin disease is characterised by IgA deposition in dermal papillae?

Answer 14

Dermatitis herpetiformis

Question 15

What can these following skin lesions be a sign of:

(a) Dermatomyotosis
(b) Dermatoherpatiformis
(c) Acanthosis Nigrans
(d) Necorobosis Lipoidica
(e) Erythema Nodosum
(f) Peritibial myxoedema

Answer 15

(a) Dermatomyositis and visceral cancer
(b) Dermatitis herpetiformis and Coeliac disease
(c) Acanthosis Nigricans and internal malignancy.
(d) Necrobiosis Lipoidica and Diabetes Mellitus
(c) Erythema Nodosum associated with infections elsewhere esp. lung, drugs, and other diseases such and IBM occasionally
(e) Pretibial myxoedema and Grave’s disease

Question 16

What populations is BCC common in?

Answer 16

The elderly and young people rarely in a condition called Gorlin’s syndrome.

BCC is the commonest malignant tumour.

Question 17

What is SCC usually due to?

Answer 17

UV radiation and so occurs in sun exposed areas. Other risks include:

• Radiotherapy
• Hydrocarbon exposure e.g. tars, mineral oils, soot
• Chronic sars/ulcers
• Immunosuppression
• Drugs

Question 18

Which skin cancer shoes a scaly appearance - BCC or SCC?

Answer 18

SCC - Clinically it presents with nodule with ulcerated, crusted surface. They often have a scaly keratinised surface as the cells prude keratin.

Question 19

What pre-malignant condition is SCC associated with?

Answer 19

Actinic keratosis

Question 20

What are physical differences between Naevus and Malenoma? Hint: ABCD

Answer 20

ABCD

Naevus are symmetrical whereas melanomas are Asymmetrical.

Naevus have even borders by melanomas have uneven Borders.

Naevus have a uniform colour but melanomas have an uneven Colour.

Naevus have a diameter less than 6mm but in melanomas the diameters is greater than this.

Another point is evolution. In melanoma the lesion is changing.

Question 21

What are risk factors for melanoma?

Answer 21

a) Sun exposure
b) Family history
c) Race - Fair complexions
d) Giant congenital naevi

Question 22

Give 3 types of Melanoma.

Answer 22

a) Nodular Meloma - This starts as a pigmented nodule and can have ulceration. It has a poor prognosis. It has invasive atypical melanocytes that invade the dermis to produce nodules of tumour cells (spread deep and can reach blood vessels). It tends to lack the superficial intradermal spread.
b) Lentigo Melanoma - Related to UV melanoma and usually found in the Face of elderly people. Presents with a Slow growing, flat, pigmented patch. Has an extensive intraepidermal component and can get very large before invading the dermis. These tends to lack BRAF mutation.
c) Acra Lentignous Melamona - found on the palms and soles of feel. Common in afro-Caribbeans. It is not associated with UV exposure. They lack BRAF mutation.

Question 23

What prognostic factor is used in Melanoma?

Answer 23

Breslow thickness - measure on microscope from granular layer of epidermis to base of tumour. the greater the thickness the lesser the 5YSR.

We also use the site - BANS - backs, arms, neck and scalp show power prognosis.

Also if the lymph nodes are are involved there is a poorer prognosis.

If there metastases before the lumps node there is an associated poorer prognosis.