Melanoma Flashcards
3 skin cancers?
Describe 3 features of melanoma
- Tumour of melanocytes
- Most important lifestyle factor = childhood sun exposure
- Easily missed - therefore Early detection is key!
Explain the pathophysiology of melanoma
UVB mutates melanocyte DNA–> melanocyte hyperplasia
Further mutations–> superficial melanoma w/in epidermis= (in situ, radial horizontal growth phase).
Later - primary melanoma invades basement membrane into surrounding dermis & becomes malignant
7 risk factors for melanoma?
- Skin type 1 and 2
- Family history
- History of sun burn/exposure & tanning beds
- Severe sunburn during childhood & teen years
- Cancer-prone syndrome (e.g. familial atypical mole or xeroderma pigmentosum)
- Immunosuppressed- HIV, medications
- Prolonged phototherapy - PUVA
3 features of typical melanoma patient phenotype?
- Skin type 1
- Multiple (>50) melanocytic naevi (moles)
- Atypical melanocytic naevi:
Large diameter, Irregular borders & Multiple colours
What is the acronym when looking at a suspected melanoma lesion?
- Asymmetry
- Border irregularity
- Colour variation
- Diameter >6mm
- Evolution- new itching, bleeding or crusting
- Ugly duckling- one mole stands out from the rest
5 differential diagnoses for melanoma?
- Lentigos
- Seborrhoeic keratoses - appears during skin ageing
- Dermatofibromas=common benign fibrous nodules, firm & tethered to the skin. Sometimes painful or itchy
- Melanocytic naevi (moles)
- Pigmented Basal Cell Carcinomas
LSDMP to remember - or an MP who takes LSD :))
Describe melanocytic naevi
vs
Describe 2 features of dysplastic atypical naevi
How to differentiate between melanoma?
Melanocytic naevi:
- Common benign skin lesion due to local melanocyte proliferation
- both congenital or acquired
- Lesion is symmetrical, clear border, uniform pigment
- People w >100 moles are at greater melanoma risk
Dysplastic atypical naevi:
- Normal moles - but have some ABCDE aspects
- Often familial + have higher rate of malignant transformation = closely monitored
- Biopsy required to differentiate between melanoma
appearance of dysplastic atypical naevi
Describe Superficial spreading melanoma (SSM)
Give 2 locations where it can occur
vs
Lentigo maligna melanoma
SSM: at sites of intense sun expo: trunk in males, legs in females (top pic)
- Most common melanoma
- Horizontal growth – radial growth phase
- Slowly enlarging flat discoloured skin
- Rapidly growing nodular melanoma can arise
LMM: (bottom pic)
- Pre-cancerous lesions.
- Sun exposed skin-especially the face in elderly
- Large macules w highly irregular borders
- Brown or black.
- Treated w surgical excision
Describe nodular melanoma
Describe Acral lentiginous melanoma
Most common type in darker skin
Dark streaks on nail beds
Describe Amelanotic melanoma
Little or no pigment due to lack of mature melanin granules
- mostly children
- Risk factors= sun-exposed skin & increasing age
4 steps for managing suspected melanoma?
a
How is dermoscopy used to stage potential melanoma?
aka 5 microscopic descriptions?
BI MUM
- Macroscopic description
- Microscopic description:
- Breslow thickness and Clark level of invasion
- Invasion of nerves or blood vessels
- Margins of excision
- Ulceration
- Mitotic rate
What is Breslow thickness and Clark’s level?
Breslow thickness is measured vertically in mm from top of the granular layer to the deepest point of tumour
Clarks level: melanoma penetration into the skin layers instead of actually measuring depth- shows anatomical plane of invasion. Deeper levels= greater metastasis risk
How can immunotherapies treat melanoma?
T cells can kill tumour cells, but tumours can turn off the T cells using as PD1 and CTLA4 on its surface
AntiPD1 (nivolumab) + AntiCTLA (ipilimumab) turn off this interaction, allowing the T-cell to destroy the tumour
