Melanoma Flashcards
What is the most common cancer in 15-24 year olds ?
Melanomas
Define what a melanoma is
- It is a potentially serious type of skin cancer, in which there is uncontrolled growth of melanocytes (pigment cells).
- It is sometimes referred to as malignant melanoma.
What is the function of melanocytes ?
To prpduce melanin, which protects the skin by absorbing UV radiation
What do non-cancerous growths of melanocytes result in ?
Moles (properly called benign melanocytic naevi) and freckles (ephelides and lentigines).
What do cancerous growths of melanocytes result in ?
Melanoma
What are the risk factors for the development of melanoma ?
- Increasing age (see above)
- Previous invasive melanoma or melanoma in situ
- Previous basal or squamous cell carcinoma
- Many melanocytic naevi (moles)
- Multiple (>5) atypical naevi (large or histologically dysplastic moles)
- A strong family history of melanoma with 2 or more first-degree relatives affected
- White skin that burns easily
- History of excess sun exposure, sunbed use or multiple sunburns
- Parkinson disease.
What is FAMMM?
- Familial atypical multiple mole melanoma syndrome.
- People who have FAMMM have > 50 moles and at least one close relative has been diagnosed with a melanoma. It increases your risk of developing melanoma
What gene is known to cause FAMMM?
CDKN2A
What do melanomas arise from ?
From otherwise normal-appearing skin (in about 75% of melanomas) or from within a mole or freckle, which starts to grow larger and change in appearance
List the different precursor lesions of melanoma
- Benign melanocytic naevus (normal mole)
- Atypical or dysplastic naevus (funny-looking mole)
- Atypical lentiginous junctional naevus (flat naevus in heavily sun damaged skin) or atypical solar lentigo
- Large or giant-sized congenital melanocytic naevus (brown birthmark).
Where on the body can melanomas develop?
- Can occur anywhere on the body but more common in areas that get a lot of sun
- Most common site in men is the back and women is the leg
- Rarely they grow on mucous membranes such as the lips or genitals & Occasionally it occurs in other parts of the body such as the eye, brain, mouth or vagina.
What are the clinical features of a melanoma ?
- The first sign of a melanoma is usually an unusual looking freckle or mole.
- A melanoma may have a variety of colours including tan, dark brown, black, blue, red and, occasionally, light grey
- During its horizontal phase of growth, a melanoma is normally flat. As the vertical phase develops, the melanoma becomes thickened and raised.
- Some melanomas are itchy or tender. More advanced lesions may bleed easily or crust over.
What are the 2 checklists which can be used to help identify if a lesion is a melanoma or not
The Glasgow 7-point checklist or the ABCDE criteria of melanoma.
What is the criteria of the Glasgow 7-point checklist ?
Major features
- Change in size
- Irregular shape
- Irregular colour
Minor features
- Diameter >7 mm
- Inflammation
- Oozing
- Change in sensation
What is the criteria of the ABCDE criteria of melanoma ?
- *A**symmetry - a melanocytic naevus (harmless mole) is usually symmetrical, whereas melanoma is often irregular or asymmetrical in shape.
- *B**order irregularity - a melanocytic naevus has smooth and even borders, whereas a melanoma often has irregular and hard-to-define borders.
- *C**olour variation - a melanocytic naevus usually has a single shade of colour or two shades of colour with one occurring inside the other or regularly repeated (generally pink, brown, or tan). Melanoma can be brown but can have as many as five or six colours (blue, black, brown, tan, grey, pink, and red). These colours are unevenly or irregularly distributed.
- *D**iameter larger than 6 mm
- *E**volving or changing - A melanocytic naevus is usually stable and does not change in size, shape, or colour, whereas a melanoma changes over time. Change in size, colour, shape, or structure may be noted over months to years.
What are the 4 main sub-types of melanoma ?
- Superficial spreading
- Acral/mucosal lentiginous
- Lentigo maligna-sun
- Nodular
Describe the typical growth pattern of superficial spreading, Acral/mucosal lentiginous & Lentigo maligna melanomas
- They first grow as macules (radial growth phase;RGP) i.e. their growth is in epidermis
- Eventually the neoplastic melanocytes invade into the dermis forming a lump (vertical growth phase;VGP)
Describe the typical growth pattern of nodular melanomas
Vertical growth phase from the outset
When can a melanoma metastasise ?
Only when it has entered the vertical growth phase i.e. invaded the dermis
In who and where do superficial spreading melanomas typically arise ?
- Typically affects the arms, legs, back and chest of young people (think trunk & limbs)
- Appearance - A growing moles with diagnostic features listed in the glasgow 7-point checklist or ABCDE checklist
Note - Amelanotic melanomas are those that lacking pigment
In who and where do Acral/mucosal lentiginous melanomas typically arise ?
- Acral - Nails, palms or soles, African Americans or Asians
- Appearance - Subungual pigmentation (Hutchinson’s sign) or on palms or feet
In who and where do lentingo maligna melanomas typically arise ?
- Chronically sun-exposed skin (face, neck, scalp) in older people
- Appearance - A growing mole with diagnostic features listed in Glasgow 7-point checklist or ABCDE checklist
In who and where do nodular melanomas typically arise & what are the characteristic features of it?
- Site varies but often sun exposed skin esp trunk & in middle-aged people
- Appearance - Red or black lump or lump which bleeds or oozes
What is the most likely type of melanoma shown due to where the lesion is situated ?
Acral melanoma of the heel
What is the most likely type of melanoma shown due to where it is situated ?
Subungual type of acral melanoma
What is the most likely type of melanoma shown due to where it is situated ?
Lentigo maligna melanoma
What is the typical dermoscopical appearance of melanomas ?
- Atypical pigment network, black dots, irregular streaks,
- Focally a blue-whitish veil and a white regression zone with hairpin vessels (atypical blood vessels that double back on themselves)
Define what is meant by breslow thickness
It is measured vertically in millimetres from the top of the granular layer (or base of superficial ulceration) to the deepest point of tumour involvement
What is the breslow thickness of a melanoma directly proportional to ?
Prognosis
