Basal Cell Carcinoma

Question 1

What are the 3 main types of skin cancer?

Answer 1

1) Basal cell carcinoma (BCC)

2) Squamous cell carcinoma (SCC)

3) Melanoma

Question 2

What is the most common cancer globally?

Answer 2

BCC

Question 3

Where is BCC more common?

Answer 3

Low latitude areas e.g. Australia

Question 4

What are BCC lesions also known as?

Answer 4

Rodent ulcers

Question 5

Where does BCC develop?

Answer 5

Upper layers of skin (basal cell layer of epidermis)

Question 6

What are the 3 layers of the skin?

Answer 6

1) Epidermis (thin outer portion)

2) Dermis (thicker inner portion)

3) Hypodermis (innermost layer)

Question 7

The epidermis can be divided into 5 layers/strata.

What are these?

Answer 7

1) Stratum basale (inner)

2) Stratum spinosum aka prickle cell layer

3) Stratum granulosum

4) Stratum lucidum

5) Stratum corneum (outer)

Question 8

What are the principal cells of the epidermis?

Answer 8

Keratinocytes

Question 9

Describe the process of keratinisation

Answer 9

The basal cells of the epidermis are undifferentiated, proliferating cells that migrate upwards through all the 5 layers.

It takes about 30 days for the cells to migrate from the basal layer to cross the stratum corneum where they are finally shed.

Question 10

What is the dermis? What does it consist of?

Answer 10

The thicker inner portion of the skin which consists of connective tissue and contains nerves, vessels and sweat glands

Question 11

What is the hypodermis? What does it consist of?

Answer 11

The innermost layer that fuses with the dermis and consists of adipose tissue and sweat glands.

Question 12

What does BCC develop from?

Answer 12

BCCs develop from mutations, usually in the PTCH and TP53 genes, affecting the basal cell layer of the epidermis.

Question 13

What genes are normally affected in BCC? (2)

Answer 13

1) PTCH

2) TP53

Question 14

Risk factors for BCC?

Answer 14

1) UV exposure

2) Fair skin

3) Ionising radiation

4) Repeated micro-injuries

5) Scars/chronic ulcers

Question 15

Where do most BCCs occur?

Answer 15

Sun exposed areas e.g. face

Question 16

Growth rate of BCC?

Answer 16

Very slow

Question 17

Metastasis rate of BCC?

Answer 17

Rarely metastasise

Question 18

What is the most common mechanism of spread of BCC?

Answer 18

Local invasion

Question 19

What 3 main types can BCC be categorised into?

Answer 19

1) nodular
2) superficial
3) morpheaform

Question 20

What is the most common type of BCC?

Answer 20

Nodular BCC

Question 21

Appearance of a nodular BCC?

Answer 21

• Pearly, shiny papules or nodules
• Small arborising telangiectasias
• Rolled borders
• Sometimes a depressed centre if ulcerated
• Lesions are very sensitive and may bleed on minor trauma

Question 22

What is the 2nd most common type of BCC?

Answer 22

Superficial BCC

Question 23

Appearance of superficial BCC?

Answer 23

Plaque or patch or well-defined, scaly, pink skin.

Some may be pigmented.

Question 24

Where do superficial BCCs more commonly occur in younger patients?

Answer 24

Trunk & extremities

Question 25

What is the least common form of BCC?

Answer 25

Morpheaform (also the poorest prognosis)

Question 26

Appearance of morpheaform BCC?

Answer 26

Poorly defined, pale scar or indurated plaque.

Question 27

Less frequently, various amounts of melanin might be present in a BCC. What is this then referred as? What may it be confused with?

Answer 27

Pigmented May be confused with melanoma

Question 28

What investigation does the definitive diagnosis of a BCC require?

Answer 28

Biopsy & histopathological examination.

Question 29

Mx of BCC?

Answer 29

Options: - surgical removal - curettage - cryotherapy - topical cream: imiquimod, fluorouracil - radiotherapy

Question 30

What 2 topical creams may be used in mx of BCC?

Answer 30

1) imiquimod 2) fluorouracil