Melanoma Flashcards
Define in-transit metastasis
intralymphatic metastasis >2cm from primary site but not beyond the nearest regional lymph node basin
5y survival vs mitotic rate (mm2) in melanoma
0: 98%
1: 98%
2-3: 96:
4-10: 91%
>11: 84%
Margins and T stage for excision of melanoma
<1mm: 10mm (T1)
1-2mm: 10-20mm (T2)
2-4mm: 20mm (T3)
>4mm: 20mm (T4)
Would you recommend a SLNB for melanom 0.8-1mm?
Depends on clinical context and other high-risk factors of the melanoma
Microsatellitosis or in-transit metastasis upgrades to N2c disease so SLNB recommended
Risk factors for melanoma
Sun exposure history
Family history
Complexion
Immunosuppression
Age
Dysplastic naevus syndrome
Previous non-melanoma skin cancers
Who would you offer a PET CT to?
Stage II disease: conflicting evidence - low yield and high false positive rate, however if true metastasis detected the clinical management and prognosis will significantly change
Stage III disease: yes before considering surgery, particularly lymphadenectomy, as may upstage the disease
Stage IV disease: yes following discussion in melanoma MDM - oligometastases that may be amenable to surgery, or equivocal findings on standard CT
What are the principles of an initial excision of a suspicious pigmented lesion
A narrow complete excision biopsy with 2mm margins, ensuring the base is not transected, and with planning for definitive wide excision in mind, ie avoiding lymphatics
Who would you offer adjuvant radiotherapy to following CLND for melanoma? (4)
> 3 nodes
node >3cm
extracapsular extension of clinically palpable disease
regionally recurrent disease
Understanding that the lymphoedema risk increases markedly
What local therapies are available for in-transit disease?
Treatment in the context of a clinical trial
IL-2 intralesional injection
Isolated limb infusion/perfusion
Radiotherapy
Laser ablation
Topical imiquimod
What is dysplastic naevus syndrome?
Used to be familial atypical multiple more and melanoma syndrome
AD mutation in CDKN2A
What naevi do melanoma develop from?
Large congenital naevi: 5-8% lifetime risk
Benign naevi if >200, or >20 on arms
Dysplastic naevi: different colour, irregular border
- monitor
What is lentigo maligna?
Lentigo maligna: melanoma in situ
Grows over years
Face, neck, hands
Often pigmented, asymmetric
Histo: malignant melanocytes propagating along base of epidermis and extending up into corneal layer
Can progress to lentigo maligna melanoma after years
What features of the histology report are important in melanoma? (7)
Breslow thickness (in mm)
Ulceration
Mitoses/hpf
Microsatellitosis
LVI/PNI
Tumour infiltrating lymphocytes
Level of dermal invasion (Clark level) - gives idea of risk of metastasis if IV/V
Superficial spreading melanoma: characteristics
Most common type of melanoma: 60%
Lower limb (women)
Back (men)
High intensity intermittent sun exposure
Asymmetric, irregular borders, different colours
Radial growth phase then invasive
Acral lentiginous melanoma: characteristics
5% melanoma
Sole of foot, palm of hand
Dark skinned people
Radial growth phase then invasive
C-KIT mutation common
Desmoplastic melanoma: characteristics
1-4% melanoma
Sun-damaged skin of head and neck
Older patients
50% amelanotic
Flat nodule, like thickened plaque
Histo: spindle celled melanocytes with fibrous stroma
Can be mixed with other melanoma (poor survival) or pure
20% local recurrence so needs wider margins
Double response to PD1 therapy due to higher tumour mutation burden
Nodular melanoma: characteristic
15% melanoma
More common in men
Amelanotic
Rapidly growing
Elevated, evolving lesion (looks like a BCC or SCC sometimes)
Aggressive
Lentigo maligna melanoma: characteristics
10-15% melanoma
Arises in precursor of lentigo maligna
Watch for change in pigmented lesion with nodule
Face, neck, hands of elderly people
High rate of recurrence 15-20%
Malignant changes of melanoma
Radial growth: atypical melanocytes dependent on growth factors from surrounding keratinocytes
Invasive phase: invade epidermis and penetrates dermis and sc tissues: now have own growth factors and are highly metastatic
S100, melan-A, SOX-10, HNB-45
BRAF mutations common, esp in chronic sun damaged skin
- targeted therapy available
CDKN2A mutation (dysplastic naevus syndrome, familial)
Indications for isolated limb infusion or perfusion for melanoma
Locally advanced tumour
Unresectable without mutation
Very large tumour
Mult satellite/in-transit mets
Invasion into adj structures
Remember ILP needs exposure of femoral vessels and ECMO
ILI is percutaneous access and a coil
What to do with melanoma lymphadenopathy and unknown primary?
Stage: CT PET, CT/MRI brain
Lymphadenectomy
Adjuvant therapy
Why do an SNB in melanoma?
Decrease the number of non-therapeutic lymphadenectomies
Identify those who may benefit from adjuvant treatment
Increase the accuracy of staging
Who is offered a lymphadenectomy in melanoma?
Clinically or radiologically positive lymph nodes
Metastatic disease where local control is desired (toilet lymphadenectomy)
Lymphadenopathy with unknown primary
High risk positive SNB
- tumour rupture
- extracapsular extension
- multiple nodes
- immunosuppressed patient
What is Cloquet’s node?
The lymphatic tissue medial to the femoral vein in the superior aspect of the femoral canal
Thought to represent the draining node into pelvis from lower limb (junction between deep inguinal nodes and external iliac nodes)
