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
When does Mohs micrographic surgery tend to be used?
- high risk areas of the face - eyes, lips & nose
- ill-defined lesions
- need for tissue sparing (minimum amount of tissue can be removed whilst ensuring the growth is gone)
When is curettage and cautery used to treat BCC?
this is less-invasive and used for lower risk BCCs on the body (rather than the face) and more superficial
it involves scraping off the lesion and burning the base
What is involved in photodynamic therapy and when would it be used?
photosensitising chemical put on the skin and then exposed to light to kill off damaged cells
it is suitable for low-risk, small, superficial BCCs
How often is PDT repeated?
There is an inflammatory reaction, maximal 3-4 days after the procedure
It must then be repeated 7 days after initial treatment
When is radiotherapy used to treat BCC?
It is used if surgery is not suitable
This is usually for large lesions and older patients
it is sometimes used if the patient has had surgery but the lesion has returned or was not fully removed
What is the topical treatment for BCC?
When is used and for how long?
Imiquimod
used for superficial low risk lesions
applied 5 times a day for 6 weeks
What is the prognosis like for BCC?
very good
patients do have an increased risk of getting other skin cancers in the future
What does the risk of recurrence of BCC depend on?
- tumour size
- site
- type
- margins
What is squamous cell carcinoma and what is it derived from?
a non-melanoma skin cancer that is derived from epidermal keratinocytes (produce keratin)
it is an invasive disease that can metastasise
(2nd most common skin cancer)
What are the causes of squamous cell carcinoma?
- exposure to UV light leading to DNA mutations
- inherited syndromes - albinism, xeroderma pigmentosum
What is albinism?
a genetic condition in which people are unable to make a normal amount of melanin
as a consequence, they have very pale skin, hair and eyes
What is xeroderma pigmentosum?
a genetic disorder in which there is decreased ability to repair DNA damage such as that caused by UV light
What are the risk factors for SCC?
- older males
- fair skin that burns easily, rarely tans (red hair)
- occupations leading to increased sun exposure
- sun damage (actinic keratoses)
- previous skin cancer
- previous cutaneous injury / thermal burn
- ionising radiation
- exposure to arsenic
- smoking
- chronic inflammation (e.g. leg ulcer)
What are actinic keratoses?
rough scaly patches on the skin that develop from years of sun exposure
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 are the clinical features of SCC?
- lesion within pre-existing actinic damaged skin
- may ulcerate
- can be tender or painful
- located on sun-exposed sites (face, lips, ears, hands, forearms, legs)
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 are the treatments for actinic keratoses?
Topical therapy:
- 5-fluorouracil (Efudix cream)
- Diclofenac sodium (Solaraze gel)
- Ingenol mebutate (Picato gel)
Cryotherapy:
- this involves freezing
How to actinic keratoses progress to SCC?
Actinic keratosis progresses to Bowen’s disease, which then progresses to SCC
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 are the treatments for Bowen’s disease?
- surgery
- cryotherapy
- photodynamic therapy
- topical therapy - 5-fluorouracil
What are the different types of SCC?
- keratoacanthoma
- cutaneous horn
- carcinoma cuniculatum
What is the main difference between BCC and SCC?
SCC involves full thickness dysplasia that breaches the epidermis into the dermis and invades deeper
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
Why must caution be taken to remove a cutaenous horn?
A cutaneous horn is not necessarily SCC and can grow out of just sundamaged skin
It needs to be removed as there may be a SCC growing underneath the horn
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 the treatment for keratoacanthoma?
It may resolve without treatment, but all keratoacanthomas need to be excised
there is no way of clincially knowing whether it is an keratoacanthoma that will resolve or there is an underlying SCC
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
What are the differential diagnoses for SCC?
- actinic keratosis
- Bowen’s disease
- keratoacanthoma
- basal cell carcinoma (can be difficult to tell the difference if they are ulcerated)
What are the characteristics for a high risk SCC?
A high risk SCC will need further monitoring and follow up
- large lesion - diameter 2cm or more
- site of lesion
- arising in the elderly or immunosuppressed
- histology - showing a thick tumour that is invading
What sites are considered high risk for a SCC?
- ear
- vermillon of lip
- central face
- hands
- feet
- genitalia
What features on the histology determine a SCC as being high risk and needing further follow-up?
- thickness of 2mm or more
- poorly differentiated
- invasion of the subcutaenous tissue, nerves and blood vessels
What are the treatments for SCC?
- surgical excision (gold standard)
- curettage & cautery
- Mohs micrographic surgery
- radiotherapy
When is radiotherapy used as a treatment for SCC?
- inoperable tumours
- patients who are unsuitable for surgery
- as an adjuvant therapy
What are the key distinguishing features of BCC?
What is the mortality rate?
- most common skin cancer
- no precursor
- surgery is the treatment of choice
- unlikely to metastasise
- lower mortality rate
What are the distinguishing features of SCC?
What is the mortality rate like?
- second most common skin cancer
- precursors include actinic keratoses & Bowen’s disease
- surgery is the treatment of choice
- more likely to metastasise
- higher mortality rate
