Melanoma Flashcards
What is 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.
What is the overall survival rate of early stage melanoma?
- Early-stage melanoma has an overall survival rate of nearly 100%, while metastatic melanoma can be rapidly fatal.
- Up to 20% of patients develop metastatic disease.
What is the cause of melanoma?
• Melanoma arises from melanocytes, the pigment-producing cells found in the skin, eye, and CNS. Aetiology relates to both genetic and environmental factors.
Genetic factors include the inheritance of sun-sensitive skin (fair skin type and susceptibility to sunburn) and specific melanoma-related genes. The major susceptibility gene associated with familial melanoma is CDKN2A, which encodes the P16 and p14ARF proteins.
Environmental factors include excessive exposure to solar and artificial UV radiation (e.g., tanning beds) and proximity to the equator.
History of sunburns and intermittent high-intensity sun exposure are more strongly associated with melanoma development than cumulative chronic sun exposure.
What regulates melanogenesis?
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.
What are the environmental factors that influences the development of melanoma?
- Environmental factors include excessive exposure to solar and artificial UV radiation (e.g., tanning beds) and proximity to the equator.
- History of sunburns and intermittent high-intensity sun exposure are more strongly associated with melanoma development than cumulative chronic sun exposure.
Which gene mutations are seen in 40-50% melanomas?
• BRAF mutations are present in approximately 40% to 50% of melanomas.
What are the different types of melanoma?
- Superficial spreading melanoma
- Nodular melanoma
• Lentingo maligna melanoma
o Frequency 5% to 15%
o Most commonly diagnosed in older people (>60 years of age) on sun-damaged skin, particularly the head and neck
o Tendency towards slow growth.
• Acral lentiginous melanoma:
o Frequency 5% to 10% but most common in people with darker skin types
o Arises on the palms, soles, and nail apparatus
o Commonly diagnosed at advanced stage
Which type of melanoma is the most common?
• Superficial spreading melanoma:
o Most common (frequency 60% to 70%)
Which body part is superficial spreading melanoma commonly seen?
o Any site, but preference for torso in men or legs in women
o Most commonly diagnosed between ages 30 and 50 years.
Which type of melanoma is the second most common?
Modular melanoma
o Second most common (frequency 15% to 30%)
o Any site
o Most frequently diagnosed in the sixth decade of life
o Rapid vertical growth and later stage at diagnosis.
Which type of melanoma has the tendency towards slow growth?
• Lentingo maligna melanoma:
o Frequency 5% to 15%
o Tendency towards slow growth.
Who is more likely to be diagnosed with lentingo maligna melanoma?
o Most commonly diagnosed in older people (>60 years of age) on sun-damaged skin, particularly the head and neck
Which type of melanoma is more likely to arise on the palms, soles and nail apparatus?
• Acral lentiginous melanoma:
o Frequency 5% to 10% but most common in people with darker skin types
o Arises on the palms, soles, and nail apparatus
o Commonly diagnosed at advanced stage
How does melanoma present?
• Altered pigmented lesion:
o A melanocytic lesion that is changing with regard to size, shape, or colour is of concern.
- > 50 benign melanocytic mole
- Atypical mole
- Melanocytic mole that does not resemble surrounding moles.
- Spontaneous bleeding or ulceration of a pigmented lesion
• Constitutional symptoms:
o Late symptoms such as weight loss, fatigue, night sweats, headache, or cough may be symptoms of systemic metastasis in a patient with a history of melanoma.
• Fixed lymphadenopathy (uncommon):
o Fixed lymphadenopathy in a patient with a history of melanoma, especially in lymph node basins draining the site of melanoma excision, are concerning for metastasis.
- Hutchinson’s sign (uncommon)
- Bluish white veil (uncommon)
What is the Hutchinson’s sign?
o 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 the bluish white veil?
o A bluish-white veiled appearance within a melanocytic lesion corresponds to dermal fibrosis, with pigmented melanophages in the dermis on histological examination of the pigmented lesion. These features represent regression and are common features of melanoma.
What is the 7-point checklist referral?
• Weighted 7-point checklist referral:
o Major features of the lesion (2 points each): change in size, irregular shape or border, irregular colour.
o Minor features of the lesion (1 point each): largest diameter 7 mm or more, inflammation, oozing or crusting of the lesion, change in sensation (including itch).
o Suspicion is greater for lesions scoring 3 points or more.
However, if there are strong concerns about cancer, any one feature is adequate to prompt urgent referral under the 2-week rule.
What are the risk factors of melanoma?
- FHx of melanoma
- Personal Hx of melanoma
- Personal hx of skin cancer
- Hx of atypical mole
- Fitzpatrick skin type 1 or 2( light-coloured skin)- pale skin with poor tanning ability.
- Red or blond hair colour
- Sun exposure or sun bed use
- High freckle density
- Increased numbers of moles
- Light eye colour like blue or green
- Large congenital mole
- Immunosuppression
- Increasing age
- Xeroderma pigmentosum- genetic syndrome with skin cancer predisposition.
What are the investigations for melanoma?
Dermatoscopy • Skin biopsy • Sentinel lymph node biopsy • LDH- used to assess metastases of melanoma but it doesn’t detect early metastases so should not be used as part of routine investigation and staging. • Further investigations include CXR and liver ultrasound, or CT scan of the chest, abdomen and pelvis. • Ultrasound of lymph nodes • Brain MRI for detection of metastases • BRAF analysis
Why do you do a dermatoscopy as part of the investigations for melanoma?
o The criteria evaluated in dermatoscopy include the presence or absence and regularity of pigment networks, dots/globules, streaks, blue-white veils, blotches, comedo-openings, leaf-like pigmentation, red-blue lacunas, and pattern of vascular structures within pigmented lesions.
o The procedure is performed to determine whether a pigmented lesion should be biopsied.
Why do you do a BRAF analysis?
o Should be performed in patients with unresectable stage IIIC and stage IV melanoma.
o Approximately 40% of melanomas contain an activating mutation in the BRAF most commonly at position V600.
What are the staging investigations done for melanoma?
o Imaging or SLNB should not be offered to people who have stage IA melanoma or those who have stage IB melanoma with a Breslow thickness of 1 mm or less.
o SLNB should be considered as a staging rather than a therapeutic procedure for people with stage IB-IIC melanoma with a Breslow thickness of more than 1 mm.
o Imaging:
CT staging should be offered to people with stage IIC melanoma who have not had sentinel lymph node biopsy, and to people with stage III or suspected stage IV melanoma.
The brain should be included as part of imaging for people with suspected stage IV melanoma.
Whole-body MRI should be considered for children and young people (from birth to 24 years) with stage III or suspected stage IV melanoma.
What are the differentials of melanoma?
- Benign mole
- Seborrheic keratosis
- Pigmented BCC
- Pigmented actinic keratosis
- Dermatofibroma
- Subungual haematoma
What is the management of melanoma?
MDT
• All patients with a suspicious pigmented skin lesion or a malignant melanoma, or where the diagnosis is uncertain, should be referred to a doctor trained in the specialist diagnosis of skin malignancy
• Stages 0-2 melanoma:
o Excision with a clinical margin
o Imiquimod for stage 0 melanoma
• Stage 3 melanoma:
o Completion lymphadenectomy if SLNC shows micro-metastases.
o Lymph node dissection with palpable stage 3 melanoma or nodal disease detected by imaging,
o Adjuvant radiotherapy offered to stage3b-3c melanoma
o Palliative treatment for in-transit metastases
• Stage 4 melanoma:
o Surgery or other ablative treatments (including stereotactic radiotherapy or radioembolisation) should be considered to prevent and control symptoms of oligometastatic stage IV melanoma in consultation with site-specific multidisciplinary teams (eg, for the brain or for bones).
