Skin cancer

Question 1

What are the effects of UVA and UVB radiation?

Answer 1

• UVA - ageing + potentiates UVB carcinogenesis

* UVB - direct DNA damage and carcinogenesis

Question 2

Actinic keratosis

Answer 2

• UVB damage + poor immune function (ageing, drugs etc)
• CF: sun-exposed areas with a scaly papule or plaque that is skin coloured/red/pigmented; may be tender or no sx
• May transform to SCC-higher risk if have >10 AK so they need removal - can do cryotherapy, superficial surgery, keratolytic + 5-FU or imiquimod creams

Question 3

Lentigo maligna

Answer 3

This is a precursor to lentigo malignant melanoma, grows over years, risk is from sun damage

CF: a slowly growing/changing skin patch, resembles lentigines then gets more atypical, often >6mm + irregular pigmentation w smooth surface

Suspect invasive when more darker colours, ulceration, bleeding, itching

M: excise

Question 4

Bowen’s disease

Answer 4

Early/in situ SCC

RF: sun, arsenic, ionising radiation, HPV, immune suppression

CF: one/more irregular scaly plaques, red/pigmented, may grow under nail causing a red streak (may destroy nail plate)

5% transform to SCC

M: excision, or if many 5-FU / imiquimod cream

Question 5

What is basal cell carcinoma?

Answer 5

A slow growing locally invasive malignant tumour of epidermal keratinocytes

Very rarely metastasises, may cause local tissue invasion + destruction

RF are UV, frequent/severe childhood sunburn, type I skin, age, male, immunosuppression, prev skin cancer, genetic syndromes, prev cutaneous injury

Question 6

What are the types and features of BCCs?

Answer 6

• Nodular (commonest): skin coloured papule/nodule with surface telangiectasia, pearly rolled edge, may have necrotic/ulcerated centre (rodent ulcer)
• Superficial: common in younger, plaque-like, slightly scaly, thin translucent rolled border, microerosions
• Cystic: soft
• Morphoeic: usually on face, plaque, indistinct borders

Question 7

How are BCCs managed?

Answer 7

• Excision with 3-5mm margins
• Mohs microscopic surgery if available + high risk areas
• Cryotherapy for small superficial
• PDT: photosensitising substance then light after a few hours, causes an inflammatory reaction. For low risk superficial
• Imiquimod or 5-FU cream: for small superficial

Question 8

What is squamous cell carcinoma?

Answer 8

Locally invasive malignant tumour of epidermal keratinocytes which can metastasise

RF are lifetime UV exposure, pre-malignant like AK, chronic inflammation like leg ulcers, immunosuppression, genetics

Question 9

How to SCCs present?

Answer 9

Keratotic ill-defined nodule, may ulcerate

• Cutaneous horn - may be a hyperkeratotic AK or a well-differentiated SCC
• Keratocanthoma - rapid growth ,dome shaped nodule, keratinous core, should remove as often are SCC
• Cutaneous invasive SCC - arise within an AK or Bowen disease
• Sebaceous carcinoma - often around eyelid

Question 10

How are SCCs managed?

Answer 10

Excision, may need MMS, radiotherapy if non-resectable

Question 11

What is malignant melanoma?

Answer 11

Invasive malignant tumour of epidermal melanocytes, most aggressive type and can metastasise to LN, lungs or brain

RF: excess UV, skin type 1, h/o multiple/atypical naevi (25% occur from an existing benign thing), prev/FH melanoma, Parkinson’s disease, precursors

Question 12

How do melanomas present?

Answer 12

ABCDE (*=major feature)
Asymmetrical*
Border irregularity
Colour irregularity*
Diameter >6mm
Evolution of lesion*

Symptoms like bleeding or itching

Can occur anywhere but most common on legs in women + trunk in men

Question 13

What are the types of melanoma?

Answer 13

• Nodular: common on trunk, related to intermittent high intensity UV (like 2w abroad every year!), vertical growth plate, may be black/ulcerated/amelanotic
• Superficial spreading: commonest early onset. Common on LL, related to intermittent high intensity UV. Spreads within epidermis then vertical into dermis
• Lentigo maligna melanoma: commonest late onset type. Common on face, long-term UV exposure
• Acral lentiginous melanoma: on palms/soles/nail beds, no clear UV relation, may see dark vertical stripes on nail or amelanotic subungual melanoma

Question 14

How is melanoma managed?

Answer 14

• Excision: 2cm margin (unless small)
• LN removal if involved
• Widespread - immunotherapies, radio, chemo
• Follow up annually for 5y in dermatology + skin self-examination

Question 15

What is the Breslow thickness?

Answer 15

The thickness of the tumour - used to guide prognosis

> 1.5mm = high risk; >4mm 40% chance of mets

Measured vertically from top of granular layer to deepest point of tumour involvement