Non-melanoma skin cancers

Question 1

What are the types of non-melanoma skin cancers?

Answer 1

basal cell carcinoma (BCC) (arise from epidermis) Squamous cell carcinoma (SCC) (arise from prickle cell layer) and its precursor lesions actinic keratoses (AK) and Bowen’s disease (BD)
keratoacanthoma (KA) and other uncommon adnexal tumours.

Question 2

What are the risk factors for NMSC?

Answer 2

UV light
Fair skin
Immunosuppression, iatrogenic as in transplant patients, HIV
Sites of chronic inflammation, scars or wounds: chronic leg ulcer, HPV infection

Question 3

What are the features of BCC?

Answer 3

80% of all NMSC
Ulceration 
Telangiectasia
Pearly white rolled edge
Nodule

Question 4

What is nodular BCC?

Answer 4

Most common, on head and neck
round, spherical, oval or dome-shaped papule or nodule with a rolled edge and pearly translucent appearance and telangectasia.
May have central ulceration
soft to firm in consistency, it exhibits slow growth and may ulcerate centrally (“rodent ulcer”) or appear cystic.

Question 5

What is superficial BCC?

Answer 5

arise on the trunk and face but can affect any part of the body.
often indistinguishable from Bowen’s disease (intraepidermal carcinoma).
slightly ulcerated, show central fibrosis and have an ill-defined border.
Biopsy soemtiems needed

Question 6

What is morpheoic BCC?

Answer 6

Sclerosing type, difficult to diagnose and presents late
Can resemble scar tissue
Edges are poorly defined, Requires Mohs micrographic surgery

Question 7

What is pigmented BCC?

Answer 7

Unevenly distributed throughout the tumour. They can sometimes resemble a melanoma.

Question 8

What is advanced and metastatic BCC?

Answer 8

Local destruction of the tissue (‘rodent ulcer’), which may eventually result in death (for example, by ulceration through the skull and into the brain).

Question 9

What are the treatments for BCC?

Answer 9

Surgical excision with margins of 4mm, deep as subcutaneous fat
Mohs micrographic surgery (MMS)
Cryotherapy
Curettage and cautery (best reserved for small well defined lesions)

Question 10

What is Mohs micrographic surgery?

Answer 10

Precise method of excising a tumour than excisional surgery with a pre-determined margin. Reserved for BCCs that are on high risk sites on the face like around the eyes and histological subtypes such as infiltrative BCC
excising the cancer, drawing a map of the excised tissue, colour-coding the margins, sectioning the fresh frozen tissues horizontally, and examining all the surgical margins while the patient waits.
5 year cure rates of 99%

Question 11

What are the other treatments available for BCC?

Answer 11

Imiquimod: Topical immune response modifier, applied 5 days a week for 6 weeks, patients may experience flu like symptoms
Photodynamic therapy: apply photosensitiser to lesion, phototoxic reaction destroys tumour, used for BCC/Bowen’s/actinic keratosis. 1 session followed by another the next week
Radiotherpay: risk of radionecrosis and complication of SCC

Question 12

What are the risk factors for squamous cell carcinoma (SCC)?

Answer 12

Sun exposure
Fair skin 
Sun beds
Old burn scars, chronic leg ulcers
Ionising radiation 
Arsenic exposure 
Smoking 
Immunosuppression 
Precursor lesions: actinic keratosis, Bowen's

Question 13

How does SCC present?

Answer 13

firm, flesh-toned, endophytic or exophytic indurated papule or nodule or a “non-healing lump” which is sore, painful, oozes, bleeds or is enlarging rapidly usually on a sun-exposed site.
lesion may be smooth, have a scaly surface and be ulcerated, crusted or hyperkeratotic.
If infected, SCC can be malodorous or fungating.
Indurated plaque, exophytic fungating nodule, keratotic nodule

Question 14

What are the prognostic high risk features for SCC?

Answer 14

Size >2 cm
Depth or invasion >2 mm thickness
Tumours extending beyond the subcutaneous tissue
Peri-neural invasion
Primary site ear or hair-bearing lip
Poorly differentiated or undifferentiated subtypes
Immunosuppression,
Failure of previous treatment- local recurrent disease is a risk factor for metastatic SCC

Question 15

What are the treatments for SCC?

Answer 15

Excision: 4mm margin or 6mm in high risk
MMS: Staged resection and evaluation of primary tumour, reserved for high risk and difficult sites
Radiotherapy
Cryosurgery: small lesions
Curettage and cautery

Question 16

What is a keratoacanthoma?

Answer 16

Starts as small papule and undergoes rapid growth into a symmetrical dome shaped, flesh-toned nodular tumour with a central crateriform core filled with a keratinous material.
Telangiectasia is often visible around the tumour. Size at presentation is 1-2 cm.
After its initial rapid growth, an indolent plateau phase is followed by spontaneous involution.
Risk factors: exposure to tar, pitch and petroleum oils
Incisional biopsy or formal excision is needed

Question 17

What is actinic keratosis?

Answer 17

Pre-malignant skin lesions with the potential to develop into SCC
result of long-term sun overexposure. They are extremely common lesions
>80% occur on the back of hands, forearms, head and neck result of long-term sun overexposure.
small, single or multiple scaly erythematous papules smaller than 1cm in diameter.
They may be flesh-toned, pink or brown and typically present on sun-exposed sites.
Rough, sore, irritation, pain

Question 18

What are the treatments for actinic keratosis?

Answer 18

25% spontaneously disappear
Cryotherapy
5-fluorouacil (5-FU): topical agent can lead to prolonged erythema and sore erosions
Surgical excision: generally unnecessary apart from cutaneous horns, hyperkeratotic or SCC is suspected
Photodynamic therapy: can be painful, very good success rate

Question 19

What is Bowen’s disease?

Answer 19

Referred as intraepidermal carcinoma or even SCC in-situ. This is a precancer and in-situ refers to the fact that the disease has not penetrated the basement membrane
asymptomatic slow growing, usually solitary, sharply demarcated, scaly erythematous patch or plaque.
Surface may be flat, scaly, eroded, velvety or verrucous. Common sites are the lower limbs and head and neck.
W>M
Punch biopsy for diagnosis

Question 20

What are the treatment options for Bowen’s disease?

Answer 20

5-fluorouracil
Cryotherapy
Curettage and cautery
Surgical excision
Photodynamic therapy
DD: psoriasis, nummular (discoid) eczema, lichen simplex chronicus, actinic keratoses, superficial BCC or SCC.