Skin cancer Flashcards
What are the 3 main types of skin cancer?
Basal cell carcinoma (75%)
Squamous cell carcinoma (20%)
Melanoma
What is basal cell carcinoma?
Slow-growing, locally invasive malignant epidermal skin tumours which are thought to arise from hair follicles/ epidermal keratinocytes, lining the bottom of the epidermis (B for Below). (aka rodent ulcer).
Give 3 risk factors for BCC.
Natural and articificial UVB exposure - cumulative DNA damage leads to mutations.
Increasing age
Skin type 1: Burns rather than tans
Family history
Geography - close to equator; high-altitude
Describe the skin changes seen in BCC.
Small, pink/pearly lump, translucent/waxy; or
Red scaly patch
Slowly grows
May become crusty, bleed or form painless ulcer
Locally invasive (rodent)
Can be pigmented in 5% -> resembles melanoma
[NHS, PTS]
Describe the distribution of lesions in BCC
Head and neck - sites of UV (sun) exposure
What investigations would you do for BCC?
Visual exam
Skin biopsy -> histology
How is BCC classified?
Based on growth patterns:
- Superficial/ in situ - superficial proliferation of neoplastic basal cells
- Infiltrative - penetrated deeper layers of skin
- Nodular - everything else.
Describe the management of BCC
- Surgical excision
2. Radiotherapy
What is the prognosis like for BCC?
Metastasis in <0.5%, but if larger, worse prognosis:
>3cm: 2% met
>5cm: 25% met
>10cm: 50% met
Other complications:
Surgical excision causes local tissue destruction
Can impinge on local structures eg nerves -> neuropathy
Recurrence (low risk)
What is Squamous Cell Carcinoma?
Locally invasive malignant tumour of keratinocytes lining the top of the epidermis (S for superficial)
Give 3 risk factors for squamous cell carcinoma.
UVB exposure
Immunosuppression
Previous SCC
Describe the skin changes seen in SCC.
Firm non-pigmented lump with rough/crusted surface.
May have a horn
Tender to touch, bleeds easily, may develop into an ulcer.
Grows over months
Sometimes resembles amelanotic melanoma.
Describe the distribution of lesions in SCC.
Sun-exposed areas, especially ear.
What investigations would you do for SCC?
Visual exam
Lesion biopsy - subcutaneous tissue and basalar epithelium needed for diagnosis, as the pathology changes with depth.
What is Bowen’s disease?
AKA Squamous cell carcinoma in situ - early form of SCC, confined to epidermis. More common in women.
Describe the management of SCC.
Excision
Radiotherapy if non-resectable
Give 2 complications of SCC.
Metastases, especially to lymph nodes.
Recurrence, esp if severe
What is melanoma?
Invasive tumour of melanocytes.
Give 3 risk factors for melanoma.
UV exposure
Skin type 1
Atypical (>5) and multiple (>100) moles
Family history
Describe the skin changes seen in melanoma
Moles: ABCDE
Asymmetrical shape
Border irregularity
Colour variability - brown, black, grey, red, white
Diameter >5cm
Evolution in size/shape/colour.
Appears to be an outlier ('ugly ducking') among surrounding moles.
Bleeding, itching.Describe the distribution of lesions in melanoma.
Men: back/chest
Women: lower legs
What investigations would you do for melanoma?
Visual exam
Biopsy (usually whole lesion excised at this point)
Sentinel node biopsy to look for metastases
What is used to assess severity of melanoma?
Glasgow 7-point checklist
3 Major criteria: changes in size, shape and colour
4 Minor criteria: inflammation, sensory change, crusting/bleeding, diameter >7mm.
Give 3 differential diagnoses for a worrying mole.
Benign pigmented naevus
Pigmented basal cell carcinoma
Pyogenic granuloma (looks like amelanotic melanoma)
Sebhorreic wart/keratosis.
What are the main types of melanoma?
Superficial spreading (70%) Lentigo maligna (10%) Nodular Acral lentiginous Amelanotic melanoma
Which type is likely in elderly people with a large dark freckle on the head or neck?
Lentigo maligna (melanoma in situ). Elderly people who spent time outside. Start flat and grow sideways, then can slowly develop and become invasive.
Which type is likely in people with pale skin and freckles? Give 1 more thing you may expect to see on visual examination.
Superficial spreading melanoma. Initially SPREAD outwards, but then downwards and affect other parts of body. Has irregular edge.
What might cause a dark fast-growing lump on the head where skin was previously normal? Give 1 more thing you might see on visual examination.
Nodular melanoma. Can grow quickly into deeper layers of skin if not removed. Head, neck, chest, back. Bleeding/oozing.
What might cause new areas of pigmentation on the palms and soles of an Asian person?
Acral lentiginous melanoma. More common in darker-skinned people.
Why is the prognosis of amelanotic melanoma poor?
They are often diagnosed late because they are skin-colour, red or pink (don’t produce melanin) and have a faint border.
Describe the management of melanoma.
Excision
Chemotherapy if metastatic
(not radiotherapy sensitive)
How common is metastases in melanoma?
50%
Give 3 sites most commonly affected by melanoma metastases.
Lung, liver, nervous system (+brain)
But can be anywhere.
Give 3 factors which improve prognosis for melanoma.
Lesion thickness <1mm Female Age <60 No ulceration (early presentation) In the limbs, rather than trunk
