Skin Cancer and Benign Lesions

Question 1

List six types of cyst

Answer 1

Epidermoid cyst - squamous epithelium, full of pus
Pilar cyst - arises from hair follicles
Steatocystoma - filled with sebum
Dermoid cyst - may contain lots of different types of mature tissue
Hidrocystoma - appears around the eyes
Ganglion cyst - develops near a joint or tendon, contains synovial fluid

Question 2

Describe seborrhoeic keratoses. Are these lesions benign or malignant?

Answer 2

Overgrowth of keratinocytes (aetiology unknown)
Warty, “stuck-on” appearance
Benign

Question 3

Describe viral warts. Are these lesions benign or malignant?

Answer 3

Rough, hyperkeratotic surface.
Usually caused by HPV (human papillomavirus)
Benign

Question 4

What is a cyst?

Answer 4

Encapsulated lesion containing fluid or semi-fluid material. Firm and fluctuant. Lots of different types of cyst.

Question 5

What is a dermatofibroma? Is it benign or malignant?

Answer 5

Benign lesion caused by proliferation of fibroblasts. Cause of proliferation is unknown but may be linked to trauma (overhealing process?)
Firm nodule, pale pink/brown with a paler centre.
Tethered to skin but mobile over fat.

Question 6

What is a lipoma? Is it benign or malignant?

Answer 6

Smooth, rubbery subcutaneous mass. Benign. No clear edge - difficult to excise

Question 7

What is an angioma? Give three types.

Answer 7

Overgrowth of blood vessels in the skin due to proliferation of endothelial cells. May occur in pregnancy and liver disease.

Cherry angioma
Spider naevi
Venous lakes

Question 8

What is a pyogenic granuloma? Is it benign or malignant? Why should this lesion be removed?

Answer 8

Benign
Rapidly enlarging red/raw growth, often at site of trauma, commonly on head/hands. Should be removed because it tends to bleed a lot.

Question 9

What is the main risk factor for the development of premalignant skin lesions, and why?

Answer 9

UV radiation

• DNA damage
• Immunosuppression

Question 10

What is Bowen’s disease?

Answer 10

Squamous cell carcinoma in situ (premalignant).
- also known as intraepidermal squamous cell carcinoma.
Full thickness dysplasia, entirely contained within the epidermis so has no metastatic potential.
Irregular, scaly, erythematous plaque.

Question 11

What are the management options for Bowen’s disease?

Answer 11

Cryotherapy
Curettage
Photodynamic therapy
Imiquimod cream (immune response modifier)

Question 12

What are actinic keratoses? Are these lesions benign or malignant?

Answer 12

Rough scaly patches on sun-damaged skin. Are flat at the base (whereas SCC looks infiltrated at the base).
Premalignant; 10% over 10 years would develop into squamous cell carcinoma if untreated.

Question 13

What is melanoma in situ? Is this benign or malignant?

Answer 13

Melanoma cells are entirely confined to the epidermis so have no metastatic potential.
Premalignant; would invade the dermis and become malignant if left untreated.

Question 14

How is melanoma in situ managed?

Answer 14

Excision

Question 15

What is cryotherapy?

Answer 15

Liquid nitrogen is used to freeze the lesion, which then forms a scab and falls off.
This works by irritating the surrounding skin enough that the immune system repairs damage and gets rid of the lesion.

Question 16

Describe the pros and cons of cryotherapy

Answer 16

Pros - cheap, easy to perform on the day

Cons - can scar, and carries risk of failure/recurrence

Question 17

What is curettage?

Answer 17

Lesion is “scraped off” using a curette

Question 18

Describe photodynamic therapy

Answer 18

A topical photosensitising agent is applies to the skin. The agent concentrated in cancerous cells. Red light is applied, causing the agent to undergo a photodynamic reaction which destroys the cells that contain the agent. This allows selective destruction of cancerous cells.

Question 19

What is imiquimod?

Answer 19

A cream (i.e. topical treatment)
Immune response modifier; stimulates cytokine release which causes inflammation and destruction of the lesion.

Question 20

Describe the pros and cons of imiquimod

Answer 20

Pros - useful when surgery is contraindicated, produces a good cosmetic result
Cons - treatment takes 6 weeks and causes significant inflammation which can be uncomfortable and/or unsightly. Also carries a risk of failure/recurrence.

Question 21

What are the two main types of non-melanoma skin cancer?

Answer 21

Basal cell carcinoma

Squamous cell carcinoma

Question 22

Describe the appearance of basal cell carcinoma

Answer 22

Pearly edge
Telangiectasia
Arborising vessels
± central ulceration

Question 23

How are moles assessed?

Answer 23

ABCDE rule:
Asymmetry (shape and colour)
Border
Colour
Diameter (>5mm)
Evolution (moles should be static, except in puberty/pregnancy)

Question 24

Describe five types of melanoma

Answer 24

Lentigo maligna
Nodular (does not have a radial growth phase)
Ocular (affects the eye)
Acral lentiginous (affects the hands/feet)
Subungal (affects the nails)

Question 25

Describe the types of primary cutaneous lymphoma

Answer 25

Cutaneous B-cell lymphoma Cutaneous T-cell lymphoma - mycosis fungoides - sezary syndrome

Question 26

Describe the main pharmacological treatment of BCC

Answer 26

Imiquimod | Topical immune-modifying agent

Question 27

What is meant by the Breslow thickness of a melnoma?

Answer 27

Breslow thickness measures (in mm) the distance between the upper layer of the epidermis and the deepest point of tumour penetration.

Question 28

Describe a key investigation for melanoma patients

Answer 28

Sentinel lymph node biopsy - this is the first node that the melanoma would drain to - inject blue dye into the scar line after wide local excision, look for dye in lymph node. Location varies depending on tumour site. Biopsy the node.

Question 29

How is melanoma treated?

Answer 29

Wide local excision, combined with chemo/immunotherapy

Question 30

Describe the surgical management of BCC (and SCC)

Answer 30

Ellipse excision | Mohs surgery if lesion is complex