Melanoma Flashcards
What is melanoma?
Malignant growth of melanocytes
What are the types of melanoma?
Cutaneous
Non-cutaneous
What are melanocytes?
Pigmented cells in the epidermis - produce melanin
What layer of the epidermis to melanocytes originate?
Stratum basale
What is the embryological origin of melanocytes?
Neural crest
What are the risk factors for melanoma?
UV radiation Skin type - Fitzpatrick 1/2 Sunburn in childhood Immunosupression Genetics
What genes predispose to melanoma?
BRAF
CDK4
What are precursor lesions to melanoma?
Benign naevus (mole) Dysplastic naevus (pre-malignant) Solar lentigo
What are differentials for melanoma?
Benign naevus (mole)
Dysplastic naevus (pre-malignant)
Spitz naevus
Blue naevus
What is a spitz naevus?
Benign lesion that looks like a melanom
What is a blue naevus?
Incomplete melanocyte migration that has the tyndall effect
What is the tyndall effect?
Incomplete scattering of light which gives a blue appearance
What are the clinical features of melanoma?
Moles
- change in size
- change in shape
What are the subtypes of melanoma?
Superficial spreading Nodular Acral lentiginous Desmoplastic Lentigo maligna
What checklist is used for melanoma?
Glasgow 7-point checkpoint
Major features
- change in size
- irregular shape
- change in colour
Minor criteria
- Diameter >6mm
- inflammation
- oozing
- change in sensation
What is superficial spreading melanoma?
Most commo type
Features
- growing moles over flat surface
- arms, legs, chest, back
What is a nodular melanoma?
Invasive form of melanoma
Features
- red/black lump
- bleeds/oozes
- sun-exposed skin
What is acral lentiginous melanoma?
Melanoma arising on palms or soles
Features
- Discolouration
- Hutchinson’s sign
What is Hutchinson’s sign?
Subungual discolouration
Discolouration of nailbed
What is desmoplastic melanoma?
Rare form of invasive melanoma
Features
- sun-exposed areas
- enlarged area of thickened skin
- variable pigmentation
What is lentigo maligna melanoma?
Malignant cells confined to epidermis
Features
- growing mole
- chronically sun-exposed skin
How is the histology of melanoma commented on?
Breslow thickness
Ulceration
Mitotic index
What is Breslow thickness?
Vertical depth from stratum granulosum
What does ulceration suggest?
Aggressive tumour phenotype
What does mitotic index show?
Indicator of cell turnover
How is melanoma staged?
AJCC system
Stage 0 = in situ melanoma
Stage 1 = thin melanoma <2mm
Stage 2 = thick melanoma >2mm, or >1mm with ulceration
Stage 3 = Melanoma spread to local lymph nodes
Stage 4 = distant mets
How is melanoma managed?
Surgical
- wide local excision
- sentinel lymph node biopsy
Medical
- adjuvant chemoradiotherapy
What is used to indicate WLE margin?
Breslow thickness
in situ = 5mm
<=2mm - 10m
>2mm - 20mm
