Skin cancer

Question 1

What are the 3 main types of skin cancer?

Answer 1

Basal cell carcinoma (75%)
Squamous cell carcinoma (20%)
Melanoma

Question 2

What is basal cell carcinoma?

Answer 2

Slow-growing, locally invasive malignant epidermal skin tumours which are thought to arise from hair follicles/ epidermal keratinocytes, lining the bottom of the epidermis (B for Below). (aka rodent ulcer).

Question 3

Give 3 risk factors for BCC.

Answer 3

Natural and articificial UVB exposure - cumulative DNA damage leads to mutations.
Increasing age
Skin type 1: Burns rather than tans
Family history
Geography - close to equator; high-altitude

Question 4

Describe the skin changes seen in BCC.

Answer 4

Small, pink/pearly lump, translucent/waxy; or
Red scaly patch
Slowly grows
May become crusty, bleed or form painless ulcer
Locally invasive (rodent)
Can be pigmented in 5% -> resembles melanoma
[NHS, PTS]

Question 5

Describe the distribution of lesions in BCC

Answer 5

Head and neck - sites of UV (sun) exposure

Question 6

What investigations would you do for BCC?

Answer 6

Visual exam

Skin biopsy -> histology

Question 7

How is BCC classified?

Answer 7

Based on growth patterns:

1. Superficial/ in situ - superficial proliferation of neoplastic basal cells
2. Infiltrative - penetrated deeper layers of skin
3. Nodular - everything else.

Question 8

Describe the management of BCC

Answer 8

1. Surgical excision

2. Radiotherapy

Question 9

What is the prognosis like for BCC?

Answer 9

Metastasis in <0.5%, but if larger, worse prognosis:
>3cm: 2% met
>5cm: 25% met
>10cm: 50% met
Other complications:
Surgical excision causes local tissue destruction
Can impinge on local structures eg nerves -> neuropathy
Recurrence (low risk)

Question 10

What is Squamous Cell Carcinoma?

Answer 10

Locally invasive malignant tumour of keratinocytes lining the top of the epidermis (S for superficial)

Question 11

Give 3 risk factors for squamous cell carcinoma.

Answer 11

UVB exposure
Immunosuppression
Previous SCC

Question 12

Describe the skin changes seen in SCC.

Answer 12

Firm non-pigmented lump with rough/crusted surface.
May have a horn
Tender to touch, bleeds easily, may develop into an ulcer.
Grows over months
Sometimes resembles amelanotic melanoma.

Question 13

Describe the distribution of lesions in SCC.

Answer 13

Sun-exposed areas, especially ear.

Question 14

What investigations would you do for SCC?

Answer 14

Visual exam

Lesion biopsy - subcutaneous tissue and basalar epithelium needed for diagnosis, as the pathology changes with depth.

Question 15

What is Bowen’s disease?

Answer 15

AKA Squamous cell carcinoma in situ - early form of SCC, confined to epidermis. More common in women.

Question 16

Describe the management of SCC.

Answer 16

Excision

Radiotherapy if non-resectable

Question 17

Give 2 complications of SCC.

Answer 17

Metastases, especially to lymph nodes.

Recurrence, esp if severe

Question 18

What is melanoma?

Answer 18

Invasive tumour of melanocytes.

Question 19

Give 3 risk factors for melanoma.

Answer 19

UV exposure
Skin type 1
Atypical (>5) and multiple (>100) moles
Family history

Question 20

Describe the skin changes seen in melanoma

Answer 20

Moles: ABCDE
Asymmetrical shape
Border irregularity
Colour variability - brown, black, grey, red, white
Diameter >5cm
Evolution in size/shape/colour.
Appears to be an outlier ('ugly ducking') among surrounding moles.
Bleeding, itching.

Question 21

Describe the distribution of lesions in melanoma.

Answer 21

Men: back/chest
Women: lower legs

Question 22

What investigations would you do for melanoma?

Answer 22

Visual exam
Biopsy (usually whole lesion excised at this point)
Sentinel node biopsy to look for metastases

Question 23

What is used to assess severity of melanoma?

Answer 23

Glasgow 7-point checklist
3 Major criteria: changes in size, shape and colour
4 Minor criteria: inflammation, sensory change, crusting/bleeding, diameter >7mm.

Question 24

Give 3 differential diagnoses for a worrying mole.

Answer 24

Benign pigmented naevus
Pigmented basal cell carcinoma
Pyogenic granuloma (looks like amelanotic melanoma)
Sebhorreic wart/keratosis.

Question 25

What are the main types of melanoma?

Answer 25

Superficial spreading (70%)
Lentigo maligna (10%)
Nodular 
Acral lentiginous
Amelanotic melanoma

Question 26

Which type is likely in elderly people with a large dark freckle on the head or neck?

Answer 26

Lentigo maligna (melanoma in situ). Elderly people who spent time outside. Start flat and grow sideways, then can slowly develop and become invasive.

Question 27

Which type is likely in people with pale skin and freckles? Give 1 more thing you may expect to see on visual examination.

Answer 27

Superficial spreading melanoma. Initially SPREAD outwards, but then downwards and affect other parts of body. Has irregular edge.

Question 28

What might cause a dark fast-growing lump on the head where skin was previously normal? Give 1 more thing you might see on visual examination.

Answer 28

Nodular melanoma. Can grow quickly into deeper layers of skin if not removed. Head, neck, chest, back. Bleeding/oozing.

Question 29

What might cause new areas of pigmentation on the palms and soles of an Asian person?

Answer 29

Acral lentiginous melanoma. More common in darker-skinned people.

Question 30

Why is the prognosis of amelanotic melanoma poor?

Answer 30

They are often diagnosed late because they are skin-colour, red or pink (don’t produce melanin) and have a faint border.

Question 31

Describe the management of melanoma.

Answer 31

Excision
Chemotherapy if metastatic
(not radiotherapy sensitive)

Question 32

How common is metastases in melanoma?

Answer 32

50%

Question 33

Give 3 sites most commonly affected by melanoma metastases.

Answer 33

Lung, liver, nervous system (+brain)

But can be anywhere.

Question 34

Give 3 factors which improve prognosis for melanoma.

Answer 34

Lesion thickness <1mm
Female
Age <60
No ulceration (early presentation)
In the limbs, rather than trunk