Skin Pathology - Melanoma, BCC, SCC

Question 1

What are the 2 layers of the skin?

Answer 1

=> Epidermis

• On top
• Stratified squamous epithelium

=> Dermis

• Connective tissue layer which provides strength and elasticity
• Contains adnexal structures, blood vessels and lymphatics

Question 2

What separates the epidermis and dermis?

Answer 2

Basement membrane

Question 3

Where can melanocytes be found?

Answer 3

Scattered along the basal layer of the epidermis, just above the basement membrane

Question 4

What is Malignant Melanoma?

Answer 4

Malignant tumour arising from melanocytes

Most cases occur in the skin

Question 5

What is the epidemiology of Malignant Melanoma?

Answer 5

• 5th most common cancer in the UK

- 2nd most common cancer in adults aged 25-49

Question 6

What are the risk factors of Malignant Melanoma?

Answer 6

• Fair skin
• Sun exposure
• Use of sun beds

Question 7

What is Acral Melanoma?

Answer 7

• Type of melanoma that occurs on palms, soles and under the nails
• Most common form of melanoma in Asian and Black ethnic groups
• Not appeared to be liked to sun exposure

Question 8

What is the method used to distinguish melanomas from benign moles?

Answer 8

=> A - Asymmetry
- Half of mole does not match the other half

=> B - Border
- Border of the mole is ragged or irregular

=> C - Colour
- Colour of mole varies throughout

=> D - Diameter
- Diameter of mole is larger than a pencil rubber

Question 9

What is Breslow thickness?

Answer 9

The thickness of the tumour measured in millimetres. Important prognostic factor that forms a part of TNM staging

Question 10

How is thickness used to determine the prognosis of melanoma?

Answer 10

• Melanomas < 0.8mm are thin and have a 100% 5 year survival rate
• Melanomas measured between 0.8-4mm have a high risk of metastasising to local lymph nodes and beyond
• Melanomas > 4mm have a very high risk of metastasising to local lymph nodes and beyond

Question 11

What is Basal Cell Carcinoma?

Answer 11

Most common type of skin cancer. Microscopically, the cells resemble the basal layer of the epidermis

Question 12

How do Basal Cell Carcinomas present?

Answer 12

• Nodule with a pearly appearance
• Some may shoe central umbilication
• Some may show ulceration

Question 13

What are the risk factors of Basal Cell Carcinomas?

Answer 13

=> Same as Malignant Melanomas:

• Fair skin
• Sun exposure
• Use of sun beds

Question 14

What are the major risk factors of Squamous Cell Carcinoma?

Answer 14

• Fair skin and cumulative UV radiation exposure
• Immunosuppression
• Chronic skin ulcers

Question 15

What is the main region where Squamous Cell Carcinomas arise?

Answer 15

Head and neck

Question 16

What is the clinical presentation of Squamous Cell Carcinomas?

Answer 16

• Irregular keratotic tumours

- They may ulcerate and crust

Question 17

How are Squamous Cell Carcinomas graded and staged?

Answer 17

=> Grading

• Well differentiated
• Moderately differentiated
• Poorly differentiated

=> Staging
- TNM system

Risk of lymph nodes metastasis is higher than BCCs, but still low

Question 18

What is Acitinic Keratosis?

Answer 18

• Form of pre-cancer
• Small, brown, scaly lesions in sun exposed sites

=> Should still be biopsied

Question 19

How are Melanomas staged and graded?

Answer 19

Melanomas are staged using the TNM system and are NOT graded. They are ALL high grades

Question 20

What is the pre-cancer form of Melanoma?

Answer 20

Melanoma-in-situ

Question 21

How are BCCs graded and staged?

Answer 21

Staged using the TNM system and are NOT graded. They are ALL low grades