Skin Cancer

Question 1

How does UV light affect the skin?

Answer 1

• Direct action on target cells (keratinocytes) for neoplastic transformation vit DNA damage
• Effects on the hosts immune system

Question 2

What is the pathophysiology of basal cell carcinoma?

Answer 2

• Most common type of skin cancer
• Mutation in DNA causes basal cell to multiply rapidly and continue growing when it would normally die
• PCTH gene mutation and sunlight exposure may predispose

Question 3

What does basal cell carcinoma look like?

Answer 3

• Nodular BCC is usually less than 1cm, pearly/shiny, often ulcerated centrally and telangiectatic
• Superficial are pearly/shiny, telangiectatic and have sun damaged skin surrounding the lesion
• Pigmented have a patch of skin with a raised edge, central depression and telangectasia
• Morphoeic/sclerotic are shiny, have a well demarcated edge and some telangectasia

Question 4

How is basal cell carcinoma treated?

Answer 4

• Excisional biopsy
• Cryotherapy
• Photodynamic therapy
• Topical agents
• Mohs micrographic surgery

Question 5

What is the pathophysiology of squamous cell carcinoma?

Answer 5

• Originates from keratinocytes
• Pre-malignant variants include actinic keratoses and Bowens disease
• Most occurs in skin regularly exposed to UV radiation

Question 6

What does squamous cell carcinoma look like?

Answer 6

• Less shiny than a basal cell carcinoma
• Ragged edges
• Hyperkeratosis

Question 7

How is squamous cell carcinoma treated?

Answer 7

• Surgical excision with a 4mm margin
• For pre-malignant you can use topical imiquimod/5-flourouracil cream, cryotherapy and photodynamic therapy

Question 8

What is the pathophysiology of malignant melanoma?

Answer 8

• Malignant tumour of melanocytes
• DNA damage (mainly UV, rarely genetic)
• Radial growth phase, then vertical growth

Question 9

What are the risk factors for malignant melanoma?

Answer 9

• Genetic markers (CDKN2A)
• Family history
• UV exposure (especially in childhood)
• Number of melanocytic naevi
• Number of atypical naevi
• Immunosuppression
• Fitzpatrick skin type I or II

Question 10

How are malignant melanomas staged?

Answer 10

Clark’s level and Breslow’s thickness

Question 11

What are the features to look for on examination of a malignant melanoma? (ABCDE)

Answer 11

• Asymmetry
• Borders (irregular, poorly defined)
• Colour (varied)
• Diameter (usually >6mm)
• Evolution

Question 12

How is malignant melanoma treated?

Answer 12

• Surgical excision (Breslow <1mm leave 1cm margin, Breslow >1mm leave 2cm margin)
• If metastatic – chemotherapy, isolated limb perfusion
• Biologic antibodies to vascular growth factors are also used
• Long term follow-up
• 5-year survival generally good

Question 13

What is Gorlin’s syndrome?

Answer 13

• Multiple BCCs
• Jaw cysts
• Risk of breast cancer

Question 14

What is Brook Spiegler syndrome?

Answer 14

• Multiple BCCs
• Trichoepotheliomas

Question 15

What is Gardner Sydrome?

Answer 15

• Soft tissue tumours
• Polyps
• Bowel cancer

Question 16

What is Cowden’s syndrome?

Answer 16

• Multiple hamartomas
• Thyroid and breast cancer

Question 17

How does BCC present?

Answer 17

• Signs/symptoms include papules with associated telangiectasias, plaques, nodules, tumours, small crusts and non-healing wounds, non-healing scabs and pearly papules and/or plaques.
• Risk factors include UV radiation, sun exposure, X-ray exposure, arsenic exposure, xeroderma pigmentosum, basal cell naevus synfrome (Gorlin-Goltz syndrome) and transplant patients.

Question 18

How does SCC present?

Answer 18

• Signs/symptoms include growing tumours, bleeding, crusting, evidence of sun damage to skin, tender or itchy non-healing wounds caused by trauma, erythematous papules or plaques, dome shaped nodules, exophytic, fungating, verrucous nodules or plaques.
• Risk factors include UV radiation exposure, immunosuppression, fair skin, hereditary skin conditions, older age, male sex, ionising radiation, carcinogens, actinic keratosis and previous skin cancer.

Question 19

Types of malignant melanoma

Answer 19

• Superficial Spreading: 80%
  
  • Irregular boarders, colour variation
  • Commonest in Caucasians
  • Grow slowly, metastasise late = better prognosis
• Lentigo Maligna Melanoma
  
  • Often elderly pts.
  • Face or scalp
• Acral Lentiginous
  
  • Asians/blacks
  • Palms, soles, subungual (c¯ Hutchinson’s sign)
• Nodular Melanoma
  
  • All sites
  • Younger age, new lesion
  • Invade deeply and metastasis early = poor prog
• Amelanotic
  
  • Atypical appearance → delayed Dx