Basal Cell Carcinoma Flashcards
What are the 3 main types of skin cancer?
1) Basal cell carcinoma (BCC)
2) Squamous cell carcinoma (SCC)
3) Melanoma
What is the most common cancer globally?
BCC
Where is BCC more common?
Low latitude areas e.g. Australia
What are BCC lesions also known as?
Rodent ulcers
Where does BCC develop?
Upper layers of skin (basal cell layer of epidermis)
What are the 3 layers of the skin?
1) Epidermis (thin outer portion)
2) Dermis (thicker inner portion)
3) Hypodermis (innermost layer)
The epidermis can be divided into 5 layers/strata.
What are these?
1) Stratum basale (inner)
2) Stratum spinosum aka prickle cell layer
3) Stratum granulosum
4) Stratum lucidum
5) Stratum corneum (outer)
What are the principal cells of the epidermis?
Keratinocytes
Describe the process of keratinisation
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.
What is the dermis? What does it consist of?
The thicker inner portion of the skin which consists of connective tissue and contains nerves, vessels and sweat glands
What is the hypodermis? What does it consist of?
The innermost layer that fuses with the dermis and consists of adipose tissue and sweat glands.
What does BCC develop from?
BCCs develop from mutations, usually in the PTCH and TP53 genes, affecting the basal cell layer of the epidermis.
What genes are normally affected in BCC? (2)
1) PTCH
2) TP53
Risk factors for BCC?
1) UV exposure
2) Fair skin
3) Ionising radiation
4) Repeated micro-injuries
5) Scars/chronic ulcers
Where do most BCCs occur?
Sun exposed areas e.g. face
Growth rate of BCC?
Very slow
Metastasis rate of BCC?
Rarely metastasise
What is the most common mechanism of spread of BCC?
Local invasion
What 3 main types can BCC be categorised into?
1) nodular
2) superficial
3) morpheaform
What is the most common type of BCC?
Nodular BCC
Appearance of a nodular BCC?
- 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
What is the 2nd most common type of BCC?
Superficial BCC
Appearance of superficial BCC?
Plaque or patch or well-defined, scaly, pink skin.
Some may be pigmented.
Where do superficial BCCs more commonly occur in younger patients?
Trunk & extremities
What is the least common form of BCC?
Morpheaform (also the poorest prognosis)
Appearance of morpheaform BCC?
Poorly defined, pale scar or indurated plaque.
Less frequently, various amounts of melanin might be present in a BCC.
What is this then referred as? What may it be confused with?
Pigmented
May be confused with melanoma
What investigation does the definitive diagnosis of a BCC require?
Biopsy & histopathological examination.
Mx of BCC?
Options:
- surgical removal
- curettage
- cryotherapy
- topical cream: imiquimod, fluorouracil
- radiotherapy
What 2 topical creams may be used in mx of BCC?
1) imiquimod
2) fluorouracil
