Skin Cancer Flashcards
What is a melanoma?
Malignant tumour arising from melanocytes
Leads to >75% of skin cancer deaths
Can arise on mucosal surfaces (e.g. oral, conjunctival, vaginal) and within uveal tract of eye
What are some risk factors for melanoma? (genetic,environmental,phenotypic)
Genetic factors
Family history (CDKN2A mutations), MC1R variants
DNA repair defects (e.g. xeroderma pigmentosum)
Lightly pigmented skin
Red hair
Environmental factors
Sun exposure – intense intermittent or chronic
Sunbeds
Immunosuppression
Phenotypic
>100 Melanocytic nevi
Atypical melanocytic nevi
What role does the MAPK (RAS-RAF-MEK-ERK) pathway play in the pathogenesis of skin cancer?
It regulates cellular proliferation, growth and migration
What are the subtypes of melanoma?
Superficial spreading
Nodular
Lentigo maligna
Acral lentiginous
Unclassifiable
How common is superficial spreading as a subtype of melanoma?
60-70% of all melanomas
Where is superficial spreading most typically found?
Trunk of men and legs of women
In superficial spreading how does growth occur?
Horizontal growth then vertical growth through the skin layers
What is the second most common type of melanoma?
Nodular
15-30% of all melanomas
Where does nodular melanoma typicaly present?
trunk, head and neck
What type of growth is shown in nodular melanoma?
Only vertical growth
What population is lentigo maligna most prevelent in?
> 60 years old
- Occurs in chronically sun-damaged skin
- Most common on face
What is lentigo maligna?
Slow growing, asymmetric brown / black macule with colour variation and an irregular indented border.
In situ – termed ‘Lentigo Maligna’
Invasive termed ‘Lentigo Maligna Melanoma’
5% of lentigo maligna progresses to invasive melanoma
Where is acral lentiginous typical presentation?
Typically palms and soles or in/around nail apparatus
What is the ABCDE for detection of melanoma?
Asymmetry
Border irregularity
Colour variation
Diameter greater than 5mm
Evolving
What is Garbe’s rule?
If a patient is worried about a single skin lesion, do not ignore their suspicion and have a low threshold for performing a biopsy
What are some poor prognostic features?
Increased Breslow thickness >1mm
Ulceration
Age
Male gender
Anatomical site – trunk, head, neck
Lymph node involvement
What is investigation for melanoma and what is to be noted about it?
Dermoscopy –can improve correct diagnosis of melanoma by nearly 50%
NB
Dermoscopic findings should not be considered n isolation
History and risk factor status are important
Excise lesion for histological assessment if in any doubt
What is the typical management for melanoma?
Primary excision down to subcutaneous fat
- 2mm peripheral margin
Wide excision
- Margin determined by Breslow depth
- 5mm for in situ
- 10mm for </=1mm
Prevents local recurrence or persistent disease
What is sentinel lymphoma node biopsy?
Lymphatic drainage of finite regions of skin drain specifically to an initial node within a given nodal basin - the ‘sentinel node’
Most likely nodes to contain metastatic disease
Currently offered for pT1b+
Extracapsular spread on lymph node biopsy – needs lymph node dissection
What imaging is done for melanoma?
Stage III, IV
And Stage IIc without SLNB
PET-CT
MRI Brain