Non Melanoma Skin Cancer Flashcards
What is basal cell carcinoma?
Where does it arise from?
it is a non-melanoma skin cancer that arises from the basal keratinocytes
it is the most common type of skin cancer in the UK (>80%)
Where are basal keratinocytes found?
along the base of the epidermis
What are the causes of basal cell carcinoma?
Exposure to UV light:
- This leads to DNA mutations and has a cumulative effect
- BCC is more common in the elderly as mutations happen over time
Hereditary:
- This is rare and tends to cause BCC in younger patients
- e.g. Gorlin’s syndrome
What is Gorlin syndrome?
It is a condition affecting many areas of the body that increases the risk of developing various cancerous and noncancerous tumours
What are the risk factors for BCC?
- older males (highest risk)
- type I or II skin (burn easily, rarely tan), red hair
- occupation leading to large amounts of sun exposure
- regular sunbathing / use of sunbeds
- sun damage (photo ageing, actinic keratoses)
- previous cutaneous injury / thermal burns
- ionising radiation
- exposure to arsenic
What are the features of BCC?
How fast does it grow?
Locally invasive skin tumour that rarely metastasises
It is a slowly growing plaque or nodule
What are the clinical features of BCC?
- varies in colour from skin-coloured to pink/pigmented
- varies in size
- called “rodent ulcer” due to spontaneous bleeding or ulceration
- rolled, pearly edges
What are the 4 types of basal cell carcinoma?
- Nodular
- Superficial
- Morphoeic
- Pigmented
How can a nodular BCC be identified?
- shiny or pearly nodule with a smooth surface
- blood vessles cross its surface (telangiectasia)
- central depression or ulceration
- edges are rolled
- most common type of facial BCC
Who tends to be affected by superficial BCC and where is it usually found?
tends to be seen in younger adults
most commonly found on the upper trunk and shoulders
What are the clinical features of superficial BCC?
- slightly scaly, irregular plaque
- thin, translucent rolled border
- multiple micro-erosions
the pearlescent colour of the edges can be seen more readily if the skin is stretched
Why do superficial BCCs tend to grow quite large?
They are often asymptomatic and the patient is not aware it is a BCC
Therefore there are more frequent delayed presentations
What is an alternative name for morphoeic BCC and where do they tend to occur?
also known as sclerosing BCC as they appear scar-like
most commonly found on mid-facial sites
What do morphoeic BCCs look like?
- waxy, scar-like plaques with indistinct borders
- pearlescent borders can be seen if the skin is stretched
What type of excision is needed for morphoeic BCC and why?
wide and deep subclinical excision
this type of BCC infiltrates deep and also has very indistinct borders that are hard to identify
Why are morphoeic BCCs thought to be higher risk?
they may infiltrate cutaneous nerves (perineural spread)
they are also more difficult to identify and treat
Why are pigmented BCCs often excised more urgently?
They can be pigmented and appear like a melanoma
Need to be extra sure that a melanoma is not being missed
What are the clinical features of pigmented BCC?
- usually nodular
- difficult to distinguish from melanoma as it is pigmented
- often is still pearlescent with rolled edges
What are the differential diagnoses for basal cell carcinoma?
- sebaceous gland hyperplasia
- squamous cell carcinoma
- malignant melanoma (pigmented BCC)
- Bowen’s disease (superficial BCC)
What are the 6 different treatment options for BCC?
- excision
- Mohs micrographic surgery
- curettage & cautery
- photodynamic therapy (PDT)
- radiotherapy
- topical therapy
What types of BCC are treated with excision?
this is the gold-standard for treating nodular BCC
it is suitable for all types of BCC
can be difficult with morphoeic BCC as it is hard to see the edges to tell when it is completely excised
How much skin is removed in excision of BCC?
What determines whether or not it has been successful?
3-4mm margin of normal skin is used
In order for it to be completely excised there must be 1mm of uninvolved skin when looking at excised lesion under the microscope
What are further steps that may need to be taken after excision?
large lesions may require a flap or graft repair
further surgery is needed if the lesion is not completely excised (1mm of uninvolved skin)
What is Mohs micrographic surgery?
This is surgery that involves examination of tissue under the microscope to ensure complete excision before closure
it has very high cure rates
What do SCC tend to look like?
How quickly do they grow?
they are enlarging scaly or crusted lumps that are keratotic
they grow over weeks to months
they are locally invasive and can metastasise
What is the most common SCC precursor?
actinic keratoses
these are erythematous, scaly papules or plaques from chronic UV exposure that affect sun-exposed sites
What is Bowen’s disease and what does it look like?
it is SCC in situ
the whole epidermis contains atypical keratinocytes (dysplasia)
it looks like a slowly enlarging scaly erythematous plaque
What does a cutaenous horn look like and what causes it?
It is caused by excessive production of keratin
The build-up of keratin forms a horn-like lesion
What is a keratoacanthoma and what does it look like?
It is a rapidly growing keratinising nodule
It forms a crater-like lesion with central keratin that looks like a volcano
What is a carcinoma cuniculatum and what does it look like?
it is a slow-growing, warty tumour on the sole of the foot
it is malignant, but due to the slow growing process, is unlikely to metastasise
