Melanoma and melanocytic lesions Flashcards
What is your next course of action when you clinically diagnose a ?melanoma ?
- Chemotherapy
- Radiotherapy
- Excisional biopsy
- Regular review in outpatients
- Wide surgical excision
A diagnosis is needed before treatment can be commenced.
Excisional biopsy
Excision biopsy confirms the diagnosis of melanoma. What is the definitive treatment of this lesion?
- Radiotherapy
- Chemotherapy
- Wide surgical excision with reconstruction
- Combined surgery and radiotherapy
- Regular review in outpatients to monitor progress
Wide surgical excision with reconstruction is the definitive treatment.
Which of the following are important prognostic factors for melanoma?
- Diameter of the lesion
- Depth of the lesion in mm
- Longevity of the lesion
- The presence of involved cervical lymph nodes
- The number of layers of the epithelium penetrated by the lesion
The Breslow depth is the depth of the lesion and
Clarke’s level the number of layers of epithelium penetrated
- these are both important prognostic factors as is the presence of involved regional nodes, indicating metastatic spread.
- A Breslow depth of ≤ 0.75mm gives a 90% 5 year survival.
Answer:
- Depth of the lesion in mm
- The presence of involved cervical lymph nodes
- The number of layers of the epithelium penetrated by the lesion
Define melanoma.
Melanoma is a malignant tumour arising from melanocytes. It is among the most common forms of cancer in young adults and typically presents as a new or changing deeply pigmented skin lesion.
How common are melanomas?
Incidence increasing
US lifetime risk is 1 in 35
Third most common skin cancer - but most common cause of skin cancer-related death. 20% develop metastatic disease.
What is the aetiology of melanoma?
Arises from melanocytes which are pigment producing cells found in the skin, eye and CNS.
Genetic factors - fair skin, susceptibility to sunburn, melanoma-related genes e.g CDKN2A or DNA repair defects in xeroderma pigmentosum.
Environmental factors - solar and artificial UV, proximity to equator.
What % of melanomas arise from pre-existing naevi (moles)?
25-42%
Name 3 different subtypes of melanoma.
- Superficial spreading melanoma (most common - 60-70%)
- Nodular melanoma - raised, vertical growth at any site
- Acral lentiguous melanoma (in darker skin, palms, soles and nails)
- Nail unit
- Amelanotic
?Lentigo maligna melanoma (head and neck in elderly)
Where does superficial spreading melanoma most commonly arise in men and women?
- Men - torso
- Women - legs
What type of melanoma growth pattern is more dangerous?
- Melanoma can grow by radial or vertical growth
- Vertical growth is more likely to result in involvement of the vasculature/lymphatics –> metastasis
How common is melanoma?
A full time GP would see 1 case every 3-5 yrs
What are the risk factors for melanoma?
- Sunbed use
- Sunburn as a child
- Cumulative sun exposure
Other:
- FHx or personal Hx of melanoma/skin cancer
- Hx of atypical naevi
- Fitzpatrick skin type I or II
- Red or blond hair colour
- High freckle density
- Light eye colour
- Many benign appearing melanocytic naevi
- Immunosuppression e.g. HIV
- Xeroderma pigmentosum - genetic syndrome with skin cancer predisposition
Apart from the ABCDE tool for diagnosis of melanoma, what other criteria can be used?
Glasgow 7 point checklist is found on each 2WW referral form for dermatology - 3 points warrants referral.
What are the signs and symptoms of melanoma?
- Often asymptomatic
- Central papular component
- Melanocytic lesion not resembling surrounding naevi
- Spontaneous bleeding/ulceration
- Constitutional symptoms
- Bluish/white veil
- Asymmetry of the lesion
- Border irregularity
- Colour variability
- Diameter >6 mm
- Evolution.
- Nodular tend to grow rapidly and not have ABCD component
- Lymphadenopathy - if metastasis
What is Hutchinson’s sign?
In the setting of pigmented bands in the nail bed and matrix (melanonychia striata), this sign shows extension of pigment into the proximal or lateral nail fold.
What is lentigo maligna?
Lentigo maligna melanoma is a type of invasive skin cancer. It develops from lentigo maligna, which is sometimes called Hutchinson’s melanotic freckle.
Lentigo maligna stays on the outer surface of the skin. When it starts growing beneath the skin’s surface, it becomes lentigo maligna melanoma.
What 2 histological criteria are used in assessment of the biopsy?
- Breslow’s thickness - good for assessing all melanomas (even the thicker ones) - from granular to bottom.
- Clark’s level - tumour thickness but less accurate than Breslow. Only good for the thinnest types of melanomas of the dermis and epidermis.
What is the ugly duckling sign?
Sign for picking out melanoma - will usually look like the odd naevi out
What are the treatment options for melanoma?
Primary tumour excision
Wide local excision - prevents local and distant recurrence; excision margin depends on thickness e.g. _<_1mm thickness do a 1cm margin.
Sentinel node biopsy - gives accurate staging; usually not done if tumour is <0.8mm without ulceration
+/- Mohs’ micrographic surgery - frozen sections are immediately analysed and this is repeated until clear margin. Considered for selected patients with minimally invasive tumours affecting ears, face or acral areas.
+/- Systemic adjuvant - for advanced disease (like IIB and IIC melanoma) or non-resectable tumours e.g. mAb against PD-1, BRAF/MEK
+/- Topical imiquimod/radiotherapy - only used if excision is impossible
NB: immunotherapies and targeted therapies have largely replaced chemotherapy.
Describe the Fitzpatrick Scale.
If a melanoma is >2mm thickness which layer does it extend into?
Dermis
What type of melanoma is this?
Superficial spreading
What type of melanoma is this?
Nodular
What type of melanoma is shown?
Acral - not related to sun exposure. More common in darker skin types.
What is shown?
Subungual melanoma
Hutchinson’s sign positive (cuticle discoloured = more likely to be melanoma
What is shown?
Amelanotic melanoma - NB: any type of melanoma can be amelanotic
What are the different types of melanocytic naevi?
Dermal - dermis only
Compound - epidermis, DEJ and dermis
Junctional - epidermis alone
What is shown?
Seborrhoeic keratosis
