Melanoma

Question 1

What are the 3 types of skin cancer?

Answer 1

Basal cell carcinoma

Squamous cell carcinoma

Melanoma

Question 2

Describe 3 features of melanoma?

Answer 2

• Tumour of melanocytes
• Most important lifestyle factor = childhood sun exposure
• Easily missed - therefore Early detection is key!

Question 3

Explain the pathophysiology of melanoma

Answer 3

UVB mutates melanocyte DNA–> melanocyte hyperplasia

Further mutations–> superficial melanoma w/in epidermis= (in situ, radial horizontal growth phase).

Later - primary melanoma invades basement membrane into surrounding dermis & becomes malignant

Question 4

7 risk factors for melanoma?

Answer 4

Skin type 1 and 2

Family history

History of sun burn/exposure & tanning beds

Severe sunburn during childhood & teen years

Cancer-prone syndrome (e.g. familial atypical mole or xeroderma pigmentosum)

Immunosuppressed- HIV, medications

Prolonged phototherapy - PUVA

Question 5

3 features of typical melanoma patient phenotype?

Answer 5

Skin type 1

Multiple (>50) melanocytic naevi (moles)

Atypical melanocytic naevi:
Large diameter, Irregular borders & Multiple colours

Question 6

What is the ABCDE assessment for suspected melanoma lesions?

Answer 6

Asymmetry

Border irregularity - uneven, scalloped/notched edges

Colour variation

Diameter >6mm

Evolution- new itching, bleeding or crusting

Question 7

5 differential diagnoses for melanoma?

Answer 7

1) Lentigos

2) Seborrhoeic keratoses - appears during skin ageing

3) Dermatofibromas = common benign fibrous nodules, firm & tethered to the skin. Sometimes painful or itchy

4) Melanocytic naevi (moles)

5) Pigmented Basal Cell Carcinomas

LSDMP to remember - or an MP who takes LSD

Question 8

Describe melanocytic naevi

Describe 2 features of dysplastic atypical naevi
How to differentiate between melanoma?

Answer 8

Melanocytic naevi:

• Common BENIGN skin lesion due to local melanocyte proliferation
• Both congenital or acquired
• Lesion is symmetrical, clear border, uniform pigment
• People w >100 moles are at greater melanoma risk

Dysplastic atypical naevi:

• Normal moles - but have some ABCDE aspects
• Often familial + have higher rate of malignant transformation = closely monitored

Biopsy required to differentiate between melanoma

Question 9

What are the 7 types of subtypes of melanoma?

Answer 9

1) Superficial spreading melanoma

2) Lentigo maligna melanoma

3) Nodular melanoma
- invasive, melanoma cells proliferate downwards through skin - vertical growth, rapidly enlarging nodule

4) Acral melanoma
- palm/sole, beneath nail, cause unknown (rare)

5) Amelanotic melanoma
- litle/no pigment, mostly children, sun-exposed skin + increasing age

Question 10

Compare features of superficial spreading melanoma (SSM) with lentigo meligna melanoma (LMM)

Answer 10

SSM:
- At sites of intense sun expo: trunk in males, legs in females
- Most common melanoma
- Horizontal growth – radial growth phase
- Slowly enlarging flat discoloured skin
- Rapidly growing nodular melanoma can arise

LMM:
- Pre-cancerous lesions.
- Sun exposed skin-especially the face in elderly
- Irregular border, abnormal colouration, large diameter
- Brown or black.
- Treated w surgical excision

Question 11

4 steps for managing suspected melanoma?

Answer 11

1) Referral to 2WW skin cancer clinic

2) Dermoscopy and clinical photographs

3) Full skin examination inclusing lymph nodes

4) Urgent excision of suspicious lesion

Question 12

How is dermoscopy used to stage potential melanoma?

aka 5 microscopic descriptions?

BI MUM

Answer 12

1) Macroscopic description

2) Microscopic description:
- Breslow thickness and Clark level of invasion
- Invasion of nerves or blood vessels
- Margins of excision
- Ulceration
- Mitotic rate

Question 13

What is Breslow thickness and Clark’s level?

Answer 13

Breslow thickness is measured vertically in mm from top of the granular layer to the deepest point of tumour

Clarks level: melanoma penetration into the skin layers instead of actually measuring depth- shows anatomical plane of invasion. Deeper levels= greater metastasis risk

Question 14

How is melanoma staged?

Answer 14

TNM staging system

Tumour – Breslow thickness, Ulceration

Nodes – how many lymph nodes the melanoma has spread to

Metastases – whether the melanoma has spread to other parts of the body

Question 15

What is a sentinel lymph node biopsy? Give one complication of it

Answer 15

Blue/radioactive dye into the site where melanoma was to travel along the lymph

Dye helps surgeon see the correct node is removed to be examined.

If central lymph node has no melanoma when examined= no further surgery. If central node is positive=worse prognosis.

Biopsy complications= lymphoedema