Skin Cancer

Question 1

What does the following image show?

Answer 1

Seborrhoeic keratoses/warts. These are benign warty lesions which have a well defined edge and often a cauliflower appearence. Common with increasing age

Question 2

What does the following image show?

Answer 2

Fibro epithelial polyps also known as skin tags

Question 3

Explain how UV light can cause cancer

Answer 3

• UV light can act on keratinocytes directly causing DNA damage which causes p53 mutations. This results in abnormal cell proliferation
• UV light can also cause immunosupression

Question 4

What are the 3 main skin cancer types

Answer 4

• Basal cell carcinoma (arising from the basal cells of epidermis)
• Squamous cell carcinoma (arising from keratinocytes in epidermis),
• Malignant melanoma (arising from melanocytes in deep epidermis)

Question 5

Describe characteristics and features of basal cell carcinomas

Answer 5

• Most common type of skin cancer.
• DNA mutation causes basal cells to multiply rapidly, accumulation of mutated cells results in formation of tumour. Can sometimes be associated with PTCH gene mutation.
• Often arise on UV exposed sites (more common in Caucasians),
• Rarely kills or metastasizes

Question 6

What does the following image show?

Answer 6

Nodular BCC. It has a shiny, pearly appearence with a rolled shoulder edge, telangectasia (lightening bolt blood vessels) and often ulceration centrally.

Question 7

What does the following image show?

Answer 7

Superficial BCC. It is shiny with a slightly rolled surface. It has threadlike vessels and ulceration

Question 8

What does the following image show?

Answer 8

A pigmented BCC. It can look similar to a melanoma. It tends to have a rolled, shiny margin and ulceration.

Question 9

What does the following image show?

Answer 9

A Morphoeic BCC. These are very subtle. May have a shiny area and tend to be much larger than they look

Question 10

What is the treatment for basal cell carcinomas?

Answer 10

Gold standard is surgical excision with 3-4mm margin.
- Curettage and cautery tends to only be done in biopsy or elderly patients. Cryotherapy again is only used in elderly. Photodynamic therapy can be very painful with high recurrence. Topical imiquimod/5-fluorouracil cream can be used. Finally Mohs micrographic surgery can be done where tissue is removed in layers.

Question 11

Describe features of squamous cell carcinomas

Answer 11

• May occur in normal skin/ burned skin or skin which has been chronically inflammed.
• Premalignant variants include Actinic keratoses and Bowen’s disease
• Higher risk of metastasis than BCC

Question 11

What does the following show?

Answer 11

A SCC. It has a heavily keratinised centre

Question 12

What is the treatment for squamous cell carcinomas?

Answer 12

Gold standard is surgical excision with a 4-5mm margin. Curettage and cautery is only used in fail patients.

Question 13

What are the treatments for premalignant squamous cell carcinomas?

Answer 13

• Topical imiquimod/5-fluorouracil cream,
• Cryotherapy,
• Photodynamic therapy

Question 14

Describe features of melanoma

Answer 14

Accounts for 75% of deaths from kin cancer. Strongly associated with UV damage, rarely genetic. The depth of penetration determines prognosis.
Can spread via lymphatics.
Also has a premalignant form

Question 15

What are the risk factors for malignant melanoma?

Answer 15

• Genetic markers,
• Family history,
• Ultraviolet irradiation,
• Sunburns during childhood,
• Atypical nevi,
• Personal history of melanoma,
• DNA repair defects such as xeroderma pigmentosum,
• Immunosuppression

Question 16

What is the Breslow depth/thickness?

Answer 16

It is a staging factors. It looks at the depth of the melanoma, measured from most superficial aspect of granular cell layer to deepest point of invasion. The deeper the melanoma, the poorer the outcome.

Question 17

What are the melanoma subtypes?

Answer 17

• Superficial spreading malignant melanoma,
• Nodular melanoma,
• Amelanotic melanoma (melanoma without the dark pigment)
• Acral Melanoma (melanoma of digits)
• Subungual melanoma,
  -Lentigo meligna melanoma (melanoma on very sun damaged skin, usually on the face)

Question 18

What are the two different melanoma precursors?

Answer 18

• Lentigo maligna (found on very sun damaged faces)
• Melanoma in situ

Question 19

What is the treatment for melanoma?

Answer 19

• Surgical excision: Breslow under 1mm requires 1cm margin. Breslow over 1mm requires 2cm margin.
• Immunotherapy (nivolumab)
  -Immune check point inhibitor (trametinib)
• Biological antibodies (for BRAF mutation - debrafanib)
• Requires long term follow up, assessment for lymph/organ spread and genetic testing in families.

Question 20

What are some examples of cutaneous tumour syndromes?

Answer 20

• Gorlin’s syndrome (multiple BCCs, jaw cysts and increase risk of breast Ca)
• Brook Spiegler syndrome (multiple BCCs and trichoepitheliomas)
• Gardner syndrome (soft tissue tumours, polyps, bowel Ca),
• Cowden’s syndrome (multiple hamartomas, thyroid and breast Ca)