Mole Flashcards
What features do you look for in a mole?
- Asymmetry: you cannot find a plane in which one half of a mole or birthmark is the mirror image of the other
- Border irregularity: blurred, notches, ragged
- Colour variation: the colour is not the same all over and may include shades of brown or black or sometimes with patches of pink, red, white or blue
- Darkness (melanomas are often very dark) or diameter >6mm across but melanomas can sometimes be smaller than this
- Evolution: has the lesion changed in any way since you first noticed it?
What is a mole?
The scientific term for a mole is a melanocytic naevus. It is composed of melanocytes, cells that lie in the basal layer of the epidermis and within the dermis. Melanocytes produce pigment: either brown or black eumelanin or red phaeomelanin within skin, hair and eyes through a process called melanogenesis. Melanogenesis is hormonally regulated by melanocyte stimulating hormone (MSH) and a number of other factors. The clinical appearance of a naevus is dependent on the pattern of melanocyte distribution within the epidermis and dermis.
What are the types of moles?
- Junctional naevus: melanocytes present at dermo-epidermal junction = brown colour and flat
- Intradermal naevus: melanocytes present in dermis = skin coloured and raised
- Compound naevus: melanocytes present at dermo-epidermal junction and within dermis = brown and raised
What sort of referrals can be done for moles?
All suspected melanomas are referred to 2 week wait cancer clinics via a HSC205 proforma. If a person has lots of moles (but not necessarily suspecting cancer) then refer within 13 weeks.
How do you determine which moles to refer?
- Moley patient - 13 weeks for risk estimation and education
- A new mole which is growing quickly in an adult - assessment within 2 weeks
- A mole which has: 3 or more colours, lost its symmetry - assessment and biopsy within 2 weeks
- A long-standing mole which is changing shape and colour - assessment within 2 weeks
- Any new nodule which is growing and is pigmented or vascular in appearance - assessment and probably monitoring or biopsy of nail bed within 2 weeks
- New pigmented line in nail - assessment and probably monitoring or biopsy of nail bed within 2 weeks
- Something growing under a nail especially if there is vascular tissue or pigment - assessment and biopsy within 2 weeks
What do you look for if suspecting cancer?
Look for evidence of metastases:
- Localised: cutaneous/SC nodules around the lesion
- Regional: lymphadenopathy
- Distant: hepatomegaly +/- splenomegaly
What is the treatment for malignant melanoma?
Only treatment for suspect malignant melanoma is excision with narrow margin (with a small no. of exceptions). This is an urgent procedure and the dermatologist will try to arrange this to happen the same day or within the week.
- Incisional/punch biopsies are not performed
What are the features of melanoma?
- ~50% of melanomas develop in pre-existing moles, the rest arise de novo
- Melanocytic naevi (moles) are both markers of risk of melanoma and potential precursors
- Most melanomas are asymptomatic. Though some patients report bleeding or itching, these symptoms can occur in normal moles if they are caught or inflamed.
What are dysplastic naevi?
Dysplastic naevi are on a continuum of progression from benign naevus to melanoma. There are some people who have a genetic predisposition to several dysplastic naevi (familial dysplastic naevus syndrome), these patients have a greater risk of developing melanoma.
What puts people at high risk for melanoma?
- People exposed to strong sunlight every now and then e.g. holidaying in a hot country are more at risk to melanoma than people who are very regularly exposed to sunlight e.g. people who work outdoors
- Sunburn is high risk at all ages
- Fair skin
- FH of melanoma
- Sunbeds - highest risk for <35yrs
- The more moles - the higher risk of melanoma, especially those with unusually shaped or large moles (atypical mole syndrome)
- IBD, HIV/AIDS, immunosuppressed, men with high BMI
- > 100 melanocytic naevi
What is the link between black people and melanoma?
It is rare for black people to get melanoma - usually it will be a type that develops on the soles of the feet or palms of the hands (acral lentiginous melanoma). This can also grow under the nail.
What is Breslow thickness?
- Measures distance in mm from the granular layer in the epidermis to the deepest level on invasion in the dermis. This is a major determinant of prognosis.
- Specialists can then decide how much normal skin to remove around the melanoma (wide local excision)
- Breslow thickness used for TNM staging and other features used too (evidence of mitosis, ulceration, lymph node involvement and evidence of distant metastases)
What adults are at risk for malignant melanoma?
- Fair or freckled skin, which burns easily or tans poorly
- A large number of moles (>100 in young people, >50 in older people)
- Atypical moles (>6 or 7mm in diameter with irregular outline and colour variation)
- History of severe sunburn, especially in childhood
- Personal or FH of melanoma
What are major signs for melanoma?
- If an existing or new mole is changing rapidly: over a period of weeks or months, rather than years
- If a mole has an irregular outline
- If a mole has different shades of black and brown
What are minor signs for melanoma?
- If a mole is >7mm in diameter or is larger than a patient’s other moles
- If a mole is inflamed or has a reddish edge
- If a mole is bleeding, oozing or crusting
- If a mole starts to feel different e.g. itching or painful
