Skin cancer Flashcards
Pathogeneis of skin cancer
At least two distinct pathways interact or converge to cause skin cancer
- Direct action of UV on target cells (keratinocytes) for neoplastic transformation via DNA damage
- Effects of UV on the host’s immune system
Main skin cancer types
- basal cell carcinoma
- squamous cell carcinoma
- malignant melanoma
Basal cell carcinoma
most common tyep of skin cancer
The process of creating new skin cells is controlled by a basal cell’s DNA.
A mutation in the DNA causes a basal cell to multiply rapidly and continue growing when it would normally die. Eventually the accumulating abnormal cells may form a tumour
PTCH gene mutation may predispose
basal cell caricnoma subtypes
- nodular
- superficial
- pigmented
- morphoeic/sclerotic
What type of BCC is this? and describe it
- Nodule ie > 0.5cm raised lesion
- Shiny “pearly”
- Telangectasia / blood vessels
- Often ulcerated centrally
nodular
What type of skin cancer is this? and describe it
Superficial
- sits on surface
- look at whole picture
- evidence of sun damage
What type of BCC is this? and decribe
Pigmented
- darker skin types
- raised
- pearly
- erythema at base
What type of BCC is this? and desccribe
- white shiny plaque
- pink
- subtle BVs
- less defined edges
Treatment - basal cell carcinoma
- Gold standard – Surgical excision 3-4mm margin
- Curettage and cautery
- Cryotherapy
- Photodynamic therapy
Squamous cell carcinoma
- may occur in normal skin or in skin that has been injured (burns) or chronically inflammated
- originates from keratinoctes
- 2nd commonest skin cancer
- skin regularly exposed to sunlight
Describe thiis squamous cell carcinoma
- rough
- scaily
- ulcerate
- no broken BVs
Treatment of squamous cell carcinoma
- Gold standard – Surgical excision 4mm margin
- Curettage and cautery
Pre-malignant /squamous cell in-situ
- Topical imiquimod / 5-fluorouracil cream
- Cryotherapy
- Photodynamic therapy
- Sun protection
Melanoma definition
malignant tumour or melanocytes
Melanoma skn cancer risk factors
- UV exposure (sunburn)
- Genetic (mutatin in CDKN2a)
- sporadic V600e (mtation of vailne by glutamate at 600), overactive BRAF sigalling
Types of melanoma
- superficial spreading
- nodular
- lentigo melanoma
Desribe superficial spreading malignant melanoma
- 70%
- plaque
- radial growth
Describe nodular melanoma
- thicker, deeper,
- vertical growth
- very dark
- raised up
Types of growht in melanoma
Radical growth: initial tendency of a melanoma to grow horizontally within the epidermis (in situ) and superficial dermal layers, often for a prolonged period. Melanoma cells do not have the capacity to metastasize, no evidence of angiogenesis
Vertical growth: With time, melanoma grows downwards into deeper dermal layers as an expansive mass lacking cellular maturation
Types of staging of melanoma
Describes how deeply it has grown into the skin, and whether it has spread
Type of melanoma staging systems:
- Clark Scale: How deeply the melanoma has gone into the different layers of skin
- Breslow scale : measures the thickness of the melanoma in the skin
- TMN staging: describes the thickness of the melanoma and whether there is any spread to lymph nodes or other parts of the body
Clark levels
5 year survival in nonulcerated tumors is 97% for Breslow thickness of 0 to 1.0 mm 91% for 1.01 to 2.0 mm
79% for 2.01 to 4.0 mm
71% for > 4.0 mm
Treatment of melanoma
- Surgical excision
- (Breslow < 1mm) – 1cm margin
- (Breslow > 1mm) – 2cm margin
- If metastatic – chemotherapy, isolated limb perfusion
- •New chemo trials
- •Vaccine therapy
- Biologic antibodies to Vascular growth factors ( bevacizumab ) or BRAF genetic defects (vemurafenib)
- Long term follow up
- Assessment for Lymph node / organ spread
- Genetic testing
Clinical features of melanom
- Most occur in skin
- May occur in oral or anogenital mucosal surfaces, oesophagus or meninges, eye
- symptomatic
Most important clinical sign is a change in the colour or size of a pigmented lesion
- Melanomas exhibit changes in pigmentation
- Borders are irregular and notched
Clincial warning signs
- Enlargement of pre-existing mole
- Itching or pain in a pre-exisiting mole
- Development of new pigmented lesion during adult life
- Irregularity of borders of a pigmented lesion
- Variegation of colour within a pigmented lesion
ABCD of melanoma
Asymmetry
Border
Colour
Diameter ( >6mm)
Evolution (change of an exisiting nevus)
EFG (only nodular melanoma)
– elevated above the skin surface
- firm to the touch
- growing
