Skin Cancer (only 2nd half) Flashcards
What are the 5 layers of skin?
Come Let’s get sun burnt!
What is melanoma
Malignant tumour arising from melanocytes
most common sc death (over 75%)
Where can melanoma arise besides regular skin
Can arise on mucosal surfaces (e.g. oral, conjunctival, vaginal) and within uveal tract of eye
genetic risk factors for skin cancer
Family history (CNKN2A mutations), MC1R variants
Lightly pigmented skin
Red hair
DNA repair defects (e.g. xeroderma pigmentosum)
environmental risk factors for melanoma
Intense intermittent sun exposure
Chronic sun exposure
Residence in equatorial latitudes
Sunbeds
Immunosuppression
phenotypic risk factors for melanoma
> 100 Melanocytic nevi
Atypical melanocytic nevi
What does BRAF substitution result in
BRAF mutations substitution leads to activation of mitogen-activated protein kinase (MAPK) pathway
melanoma
host response to melanoma
CD8+ T-cell recognise melanoma-specific antigens and if activated appropriately, are able to kill tumour cells.
CD4+ helper T-cells and antibodies also play a critical role
Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) is natural inhibitor of T-cell activation by removing the costimulatory signal (B7 on APC to CD28 on T-Cell
immunotherapy for melanoma based on
CTLA-4 blockade – ipilimumab
- Also checkpoint inhibitors (PD-1, PDL1)
subtypes of melanoma
Superficial spreading
Nodular
Lentigo maligna
Acral lentiginous
Unclassifiable
features of superficial spreading melanoma
Most frequently seen on trunk of men and legs of women
regression (visible as grey, hypo-or depigmentation), due to reaction of host immune system with tumour
After a slow horizontal (radial) growth phase, limited to epidermis, a more rapid vertically oriented growth phase, which presents clinically with development of nodule
nodular melanoma epidemiology
2nd most common type of melanoma in fair skinned individuals
Most commonly trunk, head and neck
M>F
presentation of nodular melanoma
Usually present as blue to black, but sometimes pink to red, nodule – may be ulcerated, bleeding
Develops rapidly
Nodular melanoma is believed to arise as a de novo vertical growth phase without the pre-existing horizontal growth phase
Tend to present more advanced stage, with poorer prognosis.
lentigo maligna epidemiology
Occurs in chronically sun-damaged skin, most commonly on the face
>60 years old
rarer
presentation of lentigo maligna
Slow growing, asymmetric brown to black macule with colour variation and an irregular indented border
sun exposed areas e.g neck
In situ- termed ‘Lentigo Maligna’
Invasive (5%)- termed ‘Lentigo Maligna Melanoma’
acral lentiginous epidemiology
Typically occurs on palms and soles or in and around the nail apparatus
Incidence similar across all racial and ethnic groups
why BAME groups get acral lentiginous melanomas?
As more darkly pigmented Africans and Asians do not typically develop sun-related melanomas, ALM represents disproportionate percentage of melanomas diagnosed in Afro- Caribbean (up to 70%) or Asians (up to 45%)
public awareness of early detection of skin cancer
ABCDE
Asymmetry
Border irregularity
Colour variegation
Diameter greater than 5mm
Evolving
poor prognosis indicators (melanoma)
Increased Breslow thickness >1mm
Ulceration
Age
Male gender
Anatomical site – trunk, head, neck
Lymph node involvement
how to measure breslow thickness
From granular layer to bottom of tumor
what is dermoscopy
Investigation that can improve correct diagnosis of melanoma by nearly 50%
main features of general melanoma
Asymmetry
Presence of multiple colours
Reticular, globular, reticular-globular, homogenous
Starburst
removal of melanomas
primary excision - 2mm peripheral margin
wide excision - margin determined by breslow depth - 5mm in situ, 10mm for 1mm invasion
staging of melanomas
thickness
ulceration
TNM
