DERM - Skin cancer

Question 1

What are the worrying symptoms and signs of a potentially malignant lesion

Answer 1

Clues to melanoma:
• overall pattern recognition or the ‘ugly duckling’ sign rather than formal diagnostic criteria
•New lesion
•A history of CHANGE in a naevus is concerning

Question 2

describe the epidemiology and anatomical distribution of NMSC and melanoma

Answer 2

Non-melanoma skin cancers (98%)
•BCC (67%), SCC (31%)
•Most common Cancer
•Common, usually not life threatening
•400 deaths per year (Mainly SCC)

Melanomas
(2%)
•Less common, more dangerous
•4th most common Cancer in Australia, highest rate
•Melanomas have the potential to spread internally to the lymph nodes and internal organs
•1500 deaths in Australia in 2011

The incidence of treated BCC and SCC is > 5x the combined incidence of all other cancers combined.

Question 3

Where may SCC arise from?

Answer 3

a group of disorders characterised by keratinocyte dysplasia:
–Actinic keratosis
–SCC in situ (Bowen’s disease)
–SCC

Question 4

What do melanomas arise from?

Answer 4

melanocytes

Question 5

Describe SCC (Squamous cell carcinoma)

• appearance
• common sites

Answer 5

• SCC less common but more dangerous than basal cell carcinomas.
• Rapid rate of growth, over weeks or months, greater potential to metastasize to regional lymph nodes and distant sites –Urgent assessment required
• Usually present as a thickened scaly red patch or nodule, which may bleed easily or ulcerate and may be tender.

Common sites:
chronically sun-exposed sites; hands, forearms, head, ears, lower lip and neck.

Question 6

Rx of SCC

Answer 6

Complete surgical excision with clear margins

High risk lesions may require additional adjunctive management eg radiotherapy
–Radiotherapy may be used alone if clinically warranted- eg elderly, surgical risks, size of defect

Question 7

Describe BCC (basal cell carcinoma)

• characteristic of disease
• appearance
• common sites
• how Dx
• red flag

Answer 7

Common; 2/3 of all skin cancers in Oz. Locally invasive but very rare to metastasise. more indolent/slower growth than SCC

• PEARLY nodule with central ulceration measuring about 5mm in diameter
• Telangiectasia across the lesion
• chronically exposed to the sun; head and neck > trunk > limbs.

Confirm the diagnosis with a biopsy

Red Flag: Bleeding is an important clue for the diagnosis of BCC

Question 8

What can nodular BCC mimic?

Answer 8

Melanoma if pigmented

Question 9

Describe superficial BCC (SBCC)

• appearance
• red flag

Answer 9

Superficially invasive

• Presents as slowly enlarging plaque
• May develop superficial erosion
• Red Flag: Beware the solitary red plaque not responding to topical treatment

Question 10

Rx of BCC

Answer 10

•Nodular or Infiltrating: Surgical excision with clear margins

Superficial BCCs
•Surgical excision
•Serial Curettage
•Topical Imiquimod
•Photodynamic Therapy (PDT)

Question 11

Describe actinic keratoses (solar keratoses)

• characteristic of disease
• appearance
• common sites
• Red flag

Answer 11

Very common w/ age. Can progress to invasive SCC but rare.

• Erythematous scaly lesions on dorsum of hands
• Not indurated nor tender

Sites: Sun exposed skin on the face, scalp, forearms and dorsum of hands

Red Flag: Beware of the growing hyperkeratotic and tender nodule amongst the AKs – this could be a sign of malignant transformation into SCC

Question 12

Rx of actinic keratoses

Answer 12

–Cryotherapy
–Topical: 5-FU, Imiquimod, Ingenol mebutate, diclofenac in hyaluronic acid, PDT

–Surgical excision for lesions which are
•resistant to treatment or
•suspicious for SCC

Question 13

Describe Bowen’s disease (in situ SCC)

• characteristic of disease
• appearance
• common sites

Answer 13

A type of keratinocyte dysplasia.
•It is a SCC in situ, where full thickness epidermal dysplasia is seen, but it is non invasive
•The risk of malignant transformation into SCC is estimated at 3-5%.
•These lesions are often asymptomatic, but can be itchy, painful or may bleed.

Common sites: sun exposed areas, esp lower limbs.

Question 14

Rx of Bowen’s disease

Answer 14

–Topical
•5-FU, Imiquimod, PDT

–Surgical excision for lesions which are
•resistant to treatment or
•suspicious for SCC
•certain high risk patient groups

Question 15

Examples of pigmented lesions

Answer 15

•Lesions of melanocytes
–Benign naevi
–Malignant melanoma

•Also, some lesions which look pigmented, but are not melanocytic in origin
–Eg pigmented BCC, pigmented actinic keratosis, seborrhoeic keratoses, solar lentigines- due to melanin or keratin

Question 16

Describe characteristics of benign moles

Answer 16

• Tend to be small
• Evenly coloured
• Regular edges
• 1 colour
• Symmetrical
• Does not “stand out”
• Does not change with time

Question 17

Describe pigmented solar keratoses

Answer 17

• Middle-aged people
• Sun-induced
• Usually scaly and erythematous, but can be pigmented
• Rough surface

Question 18

Describe characteristics of dysplastic naevi

• size
• colours
• borders
• what is it an independent risk factor for?

Answer 18

• Naevi which show atypical features both clinically and histologically but are not malignant melanoma
• Larger (>5mm)
• Atypical pigment net on dermoscopy
• 2 or more colours
• Smudgy borders
• Generally still symmetrical

Independent risk factor for development of melanoma, especially if several

There is no place for the prophylactic excision of dysplastic naevi but if melanoma suspected, it should be excised urgently

Question 19

What are (11) risk factors for melanoma?

Answer 19

–Multiple dysplastic naevi (more than 5)
–Multiple (>100) typical naevi
–Past history of melanoma
–Strong family history (1 or more first degree family members)
–History of blistering sunburns (esp. childhood)
–Previous non-melanoma skin cancer
–Type 1 skin (burns easily with no tanning)
–Freckling
–Blue eyes
–Red hair
–Immunosuppression

Question 20

Common sites of melanoma distribution in women & men

Answer 20

Women: legs
Men: trunk, head & neck

Question 21

Px of melanoma

Answer 21

A - Asymmetry
B - Border irregularity
C - Colour variegation
D - Diameter (>5 mm)
E - Evolution (any changing lesion)

N.B: some subtypes of melanoma do not fulfil these criteria & Many benign lesions may satisfy all the ABCDE criteria (e.g. seborrhoeic keratoses or dysplastic naevi)

Question 22

What are (4) melanoma subtypes?

Answer 22

• Superficial spreading melanoma (SSM): 80% of melanomas. Usually follow the ABCDE rules. Evolves over weeks to months
• Lentigo maligna: very slow evolution.
• Acral lentiginous melanoma
• Nodular melanoma: often do not fulfil ABCDE criteria. Rapid growth & early invasion. Common in older males (less doctor visit). Follow an EFG rule

Question 23

How do nodular melanomas present?

Answer 23

EFG (rather than ABCDE)
•Elevated
•Firm
•Growing

If in doubt, excise completely and urgently

Question 24

Describe (2) biopsy techniques in skin cancer

- what are they recommended for

Answer 24

1. Partial biopsies (not recommended for pigmented lesions – sampling error)
   •Punch biopsy (2-3mm biopsy punch into lesion)
   •Shave biopsy (shave across lesion into dermis. Not good for assessing depth of lesion)
2. Excisional biopsies (best for pigmented lesions)

Punch biopsy & shave biopsy are appropriate Ix to confirm the diagnosis of NMSC but be aware of limitations

Question 25

What determines the excision margins for melanoma?

Answer 25

Breslow thickness

E.g.

• in situ thckness -> 5mm margin
• 1cm margin etc

Question 26

Prognosis of melanoma

Answer 26

Survival depends on the depth

• In situ: 100%
• 4mm: 45-67%

Other factors determining prognosis:
–Ulceration, mitotic rate
–Age, sex, other patient factors
–Location

Question 27

Advise on sunprotection

Answer 27

1. SLIP on a shirt
2. SLOP on some sunscreen
3. SLAP on a hat
4. SEEK shade
5. SLIDE on some sunglasses…