Skin cancer

Question 1

BCC

Answer 1

slow growing, locally invasive malignant tumour

Question 2

BCC risk factors

Answer 2

UV exposure

Immunosuppression

Fitzpatrick type 1

Family history of skin cancer

Xeroderma pigmentosum

Older patients

Previous personal history of skin cancer

Question 3

BCC genes

Answer 3

PCTH gene

p53 gene

Question 4

BCC clinical features

Answer 4

Majority occur on sun-exposed areas of the head & neck

Small slow-growing lesions

Raised pearly edges & evident telangiectasia

Rarely cause systemic symptoms

If left to grow → pain, bleeding & ulceration or subsequent invasion into surrounding tissues

Question 5

BCC types

Answer 5

Nodular (most common) - pink pearly nodule with telangiectasia & can become ulcerated or encrusted

• subtypes = cystic, pigmented or keratotic

Superficial - younger patients

• erythematous scaly plaques with a thread-like border & may bleed + ulcerate

Morphoeic - highest risk of reoccurrence

Basosquamous - mix between BCC + SCC

Question 6

BCC ddx

Answer 6

Trichoepithelioma

Keratoacanthoma

Cutaneous SCC

Question 7

BCC ix

Answer 7

Largely clinical diagnosis based on visualisation under dermascope

Can only be confirmed diagnosis through excision biopsy

Question 8

BCC mx

Answer 8

Depends on the size & where

Small lesion < 2cm, low risk & superficial → surgical excision and topical treatments

Larger lesion > 2cm, high risk, invasive → Moh’s micrographic surgery

Unable to have surgery → radiotherapy

Topical treatments = cryotherapy, photodynamic therapy, immune response modulator, topical chemotherapy, curettage & electrocautery

Question 9

BCC complications

Answer 9

Recurrence

Local invasion

Metastases (rare) - lymph nodes, bones & lungs

• radiotherapy & palliative treatment

Question 10

BCC prevention

Answer 10

Reduce exposure to UV light and avoid sunbeds

Frequent use of SPF50 sunscreen & wearing of protective clothing

Question 11

SCC

Answer 11

Locally invasive malignant tumour of the epidermal keratinocytes which has potential to metastasise

Question 12

SCC RFs

Answer 12

Smokers

Immunosuppression

Elderly

Chronic skin inflammation

Pre-malignant conditions - Bowen’s disease (irregular scaly plaque usually on sun exposed areas)

Genetic predisposition

Question 13

SCC clinical features

Answer 13

Highly variable appearance

Can appear nodular, indurated or keratinised with associated ulceration or bleeding

Growth may be over weeks to months

Typically located on sun-exposed sites, eg. hands, forearms, lower limbs & ‘H zone’ of the face

Question 14

SCC ddx

Answer 14

Other forms of skin cancer

Pre-malignant conditions - bowen’s disease or actinic keratosis

Verrucous carcinoma

Question 15

SCC types

Answer 15

Cutaneous horn

Keratoacanthoma

Carcinoma cuniculatum

Marjolin ulcer

Question 16

SCC ix

Answer 16

H&E

Dermoscopy is recommended to aid diagnosis → white circles/structureless areas, looped blood vessels & central keratin plug

Definitive diagnosis = biopsy

Lymph node/metastasis → further imaging +/- fine needle aspiration

Question 17

SCC classification

Answer 17

Broder’s grade - determined by the ratio of differentiated to undifferentiated cells

Question 18

SCC mx

Answer 18

Surgical treatment - excision biopsy

Further wide local excision, Mohn micrographic surgery or adjuvant radiotherapy may be offered to patients with one/more involved

Non-surgical treatment - multiple options available

• primary radiotherapy if surgery not feasible
• immune checkpoint inhibitors - locally advanced SCC whether other options not reasonable
• chemotherapy - third line

Question 19

MM types

Answer 19

Superficial spreading - large, flat & irregularly pigmented lesions, aged 30-50 years

Nodular - rapidly growing, pigmented, bleeding, or ulcerated nodule, typically > 50 years

Lentigo maligna melanoma - large flat pigmented lesions, often in the older population

Acral lentiginous - variable pigmentation, often present with appearance of a stain, typically large size at presentation

Question 20

MM genes

Answer 20

MAPK pathway - BRAF & NRAS proto-oncogenes

CDKN2A/RB1 pathway - p16 and p14ARF

Question 21

MM RFs

Answer 21

UV exposure

Age

Previous melanoma

Skin tone - highest in caucasians

Family history

Predisposing conditions - albinism, xeroderma pigmentosum, atypical mole syndrome

Parkinson’s disease !

Question 22

MM clinical features

Answer 22

New skin lesion or a change in the appearance of a pre-existing mole

May be associated bleeding or itching

ABCDE - asymmetry, border irregularity, colour uneven, diameter > 6mm, evolving lesion

Question 23

MM ddx

Answer 23

Benign = junctional or compound naevi, intradermal naevi, blue naevi or spitz naevus

Malignant = pigmented basal cell carcinoma, pyogenic granuloma, seborrheic keratosis, kaposi sarcoma

Question 24

MM ix

Answer 24

Excisional biopsy - confirms diagnosis

Question 25

MM histological features

Answer 25

Can determine both management or prognosis

Breslow thickness

Degree of ulceration

Histological subtype

Immunohistocytochemistry

Mitotic rate

Question 26

MM mx

Answer 26

Specialist skin MDT

Ongoing sun protection advice should be given with concurrent vitamin D supplementation & advice on prevention

Wide local excision - indicated in nearly all cases of melanoma

• exact peripheral margin used in wide local excision is guided by the Breslow thickness

Sentinel lymph node biopsy - aims to identify whether or not there is any melanoma in the primary draining lymph node → staging and prognostic procedure only

Metastatic disease - various immunotherapy & chemotherapy agents

Question 27

MM staging

Answer 27

CT C/A/P & MRI brain

TNM staging → guides treatment and prognosis