Dermatology - Skin Tumours Flashcards
What is a melanocytic naevus?
A pigmented mole - melanocytic naevus is a type of melanocytic tumour (benign) that contains naevus cells (composed of melanocytes).
It can be a direct precursor lesion of melanoma
What are the 3 types of melanocytic naevi
Junctional naevus – Between the epidermis and the dermis, flat, usually mid to dark brown.
Compound naevus – Within the dermis and at the epidermal-dermal junction, raised centre with a flat surrounding area, often hairy.
Intradermal naevus – Within the dermis, raised, often hairy, paler.
What is melanoma?
A malignant tumour arising from melanocytes (pigment cells)
What is melanoma?
A malignant tumour arising from melanocytes (pigment cells) in the skin.
- In situ → confined to epidermis
- Invasive → spread to dermis through basement membrane
- Metastatic → spread to other tissues via lymphatic system or to organs via bloodstream
How are in situ melanomas cured?
With excision
What is the risk of recurrence and/or metastasis of melanomas based on?
Breslow thickness
What is Breslow thickness?
Breslow thickness is the measurement of the depth of the melanoma from the surface of your skin down through to the deepest point of the tumour.
- <1mm thick = low risk
- 1-4mm thick = intermediate risk
- >4mm thick = high risk
What layer of the epidermis are melanocytes found in?
Basal layer
What do melanocytes produce?
Melanin
What is melanin?
A protein that protects skin cells by absorbing UV.
Are melanocytes found equally in black and white skin?
Melanocytes are found in equal numbers in black and white skin, but melanocytes in black skin produce much more melanin (dark brown/black skin less likely to be damaged by UV radiation).
What is the most common type of melanoma?
Superficial spreading melanoma
How does superficial spreading melanoma grow?
Grows flat and horizontally first (spread within epidermis) and later grows vertically
What is the most aggressive form of melanoma?
Nodular
How does nodular melanoma grow?
Grows rapidly in the vertical plane
What are the 4 types of melanoma
- Superficial spreading melanoma (most common)
- Nodular melanoma (most aggressive)
- Lentigo maligna melanoma
- Acral lentiginous melanoma
What type of melanoma occurs on palms/soles and under nails?
Acral lentiginous melanoma
What is amelanotic melanoma?
melanoma with no pigment
What is the ABCDE of melanoma?
The ‘ABCDE’ of melanoma is an acronym designed to help the public and clinicians identify features in a skin lesion that may suggest an early or in situ melanoma
- Asymmetry
- Border irregularity (melanoma often has a ‘scalloped’ border)
- Colour variation (a variegated lesion consists of many colours)
- Diameter >6mm
- Evolves over time (size, shape)
Other symptoms: bleeding, itching, pain
What diameter would indicate potential melanoma?
>6mm
If a lesion has any of the ABCDE features, what should you do?
If a lesion has any of these features, it should be referred urgent under the 2 week wait pathway for suspected malignant melanoma
What is the 7 point check list for melanoma?
- Major signs:
- Change in size
- Change in shape
- Change in colour
- Minor signs:
- Diameter >7mm
- Inflammation
- Altered sensation
- Crusting/bleeding/oozing
How is Breslow thickness established?
Using histology
What is a strong predictor of outcome in melanoma?
Breslow thickness
What Breslow thickness indicates the need for a sentinel node biopsy?
>1mm - look for evidence of metastases and stage the cancer
What staging system is used for melanoma?
TNM:
- Stage 0 – In situ melanoma
- Stage 1 – Think melanoma <2mm in thickness
- Stage 2 – Thick melanoma >2mm in thickness, or >1mm thickness with ulceration
- Stage 3 – Melanoma spread to invade local lymph nodes
- Stage 4 – Distant metastases
What is basal cell carcinoma?
A locally invasive tumour of the epidermal (basal) keratinocytes.
Give some risk factors for basal cell carcinoma
- Type I or II skin (fair skin which always burns and never or rarely tans)
- History of frequent or severe previous sun burn
- Outdoor occupation or hobbies
- Personal or FH of skin cancer
- Immunosuppression
- Increasing age
- Male sex
- Gorlin’s syndrome (rare, hereditary)
What is the most common type of skin cancer?
Basal cell carcinoma