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
Describe the management of melanoma following confirmed diagnosis
What are the recommended margins?
Wide local excision (WLE) dependent on Breslow thickness and margins
Sentinel lymph node biopsy (SLNB)
Margins recommended:
- In situ: 5mm
- Breslow <1mm: 10 mm
- Breslow 1–2mm: 10–20 mm
- Breslow >2mm: 20 mm
How is melanoma staged?
TNM staging system
- Tumour – Breslow thickness, Ulceration
- Nodes – how many lymph nodes the melanoma has spread to
- Metastases – whether the melanoma has spread to other parts of the body
Describe the role of lymphatics in cancer spread
If they travel through the lymph system, the cancer cells may end up in lymph nodes and can grow there= metastasis
What is a sentinel lymph node biopsy? Give one complication of it
Blue/radioactive dye into the site where melanoma was to travel along the lymph
Dye helps surgeon see the correct node is removed to be examined.
If central lymph node has no melanoma when examined= no further surgery. If central node is positive=worse prognosis.
Biopsy complications= lymphoedema
What is the treatment of melanoma? + 4 followups?
Treatment of melanoma=removing the lesion
Follow up 3monthly after diagnosis to detect early recurrence:
- Full skin check
- Recurrence in scar
- Lymph nodes
- Organomegaly
Give an example of targeted melanoma therapy which can be used in approx half of melanoma patients
What is the limitation of this targeted therapy?
In 50% of melanoma a mutation in the BRAF gene leads to uncontrollable cell growth
BRAF inhibitors + MEK inhibitors can therefore block this pathway
HOWEVER - melanomas can acquire resistance to these drugs!
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
Give the prognosis for melanoma
Overall survival –92%
Determined by Breslow thickness:
- <1mm thickness: 95% 5yr survival
- > 4mm thickness: 60% 5 year survival
- LN spread, stage III: 70% 5 year survival
- Distant spread (skin, lung, brain, liver, bones), stage IV: 55% 1 year survival
