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Mladeži u dečjem uzrastu: dogma i fakat. Marko B. Lens, MD PhD FRCS. Naevi (Moles). Melanocytic lesions of the skin Children may present a variable spectrum of melanocytic skin lesions and the great majority of them is benign.
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Mladeži u dečjem uzrastu: dogma i fakat Marko B. Lens, MD PhD FRCS
Naevi (Moles) • Melanocytic lesions of the skin • Children may present a variable spectrum of melanocytic skin lesions and the great majority of them is benign. • Naevi can be congenital or acquired developing in childhood and early adulthood • New lesions rare after age of 30 to 35, unless belong to very moley family • Naeviinvolutes with age
Naevi and age Heterogeneity between naevi induction and involution processes
Melanocytic naevi Junctional Compound Intradermal
Other types of melanocytic naevi • Dysplastc inaevus (nevus of Clark): usually a compound nevus with cellular and architectural dysplasia. Larger then normal moles and tend to have irregular colour and borders. • Blue naevus • Spitz naevus – a distinct variant of intradermal nevus, usually in a child. They are raised and reddish (non-pigmented)
Other types of melanocytic naevi • Giant hairy naevus (with an associated lifetime risk of melanoma in 4%-10% of patients) • Naevus of Ito and Naevus of Ota (congenital, flat brownish lesions on the face or shoulder)
Atypical mole syndrome • More than 100 naevi • Naevi on breasts, buttocks, fingers, feet, scalp • Affects 2% of normal population • 10 to 20 time increased risk of melanoma • Up to 15% of melanoma cases • Refer to a dermatologist • No need to excise lesions for the purpose of confirming dysplasia or as a prophylaxis
Naevi • Strongest risk factor for melanoma • Odds ratios between 2 to 20 • Stable risk across all continents despite different UV exposure • Atypical naevi significant risk factor for melanoma • Site also important. Legs for females and trunk for males • 50 to 60% of all melanomas grow from a mole but also can appear on normal skin with no pre-existing mole
Sun and melanocytic naevi (MN) • Total sun exposure and tendency to burn are independent risk factors for MN incidence. • Lifetime number of sunburns and the severity of sunburns are significantly related to the presence of largeacquired MN. • Reducing the total number of hoursof sun exposure is particularly relevant in sun-sensitive childrenand may restrain the development of MN, whereas avoiding sunburnin young children might prevent large MN, subsequently reducingthe risk of melanoma.
Figure 1 Naevus counts equal or above 50 and risk of melanoma
Risk of melanoma in relation to naevi above 5 mm in diameter
Suspicious naevi • Change in weeks or months • Not years • Irregular in colour and/or shape with recent change • Bleeding and crusting lately • Itching not very specific • Geographical border • Regression (blueish/grey veil) • The “odd” one out
Managing uncertainty: cannot identify lesion Correct Diagnosis Correct Management No Diagnosis Incorrect Management Avoid removing any lesion where you are uncertain of the diagnosis
Management of naevi • Does it need removing? • Can you reassure the patient? • Should you remove it? • Can you remove it? • Consider site, size, experience & patient
Management of naevi: Basic principles • Not everything needs to be removed • Diagnosis and reassurance may be enough • Stable and unchanging, reassure • Draw & measure lesion, review after 6-12 weeks • Advise patient to return if any change • Time as a diagnostic tool
Management: Basic Principles • Send everything for histological examination • See and understand the histology report • Know how to manage the histology report
Melanocytic skin lesions: Dermatological techniques • Ellipse excision • Curettage &cautery • Shave excision
Pyogenic granuloma ??? • Urgent surgery • Histology • Amelanotic melanoma
Melanoma in children • Melanoma in children is rare • Only 0.3% to 0.4% of all melanomas occur in prepubertal age • 1.3% to 2% occur in patients younger than 20 years • The incidence of MM in children is estimated to be 0.7 per million per year in children aged 0 to 9 years, whereas it is 13.2 per million per year in people aged between 15 and 19 years • This incidence is continuing to rise. • Recent data suggest an increasing incidence even in young age
Pediatric melanoma Versus Adult melanoma • Lymph node metastases were more prevalent in young patients with melanoma compared with adult (thickness-matched) control patients • 5- and 10-year survival rates were similar. • Higher percentage of young melanoma patients have positive family histories and have atypical nevi suggest that a stronger predisposing genetic component may be operant in this group.
Risk of melanoma and family history • Familial clustering of melanoma occur in around 1% of melanoma cases • One parent affected: RR 2.40(2.10-2.72) • One sibling affected: RR 2.98(2.54-3.47) • One parent plus one sibling: RR 8.92(4.25-15.31) • One parent multiple MMs: RR 61.78( 5.82-227)
Melanoma and germline mutations CDKN2A the most common gene altered in melanoma families • Can affect the p16 and the p14 protein • CDK4 mutations are rare • CDKN2A accounts for up to 25% of melanoma families • p16 involved in cell cycle and senescence
Genes et Naevus • 60% of the variation in naevus number is determined by genetic factors • Twin studies. St Thomas. More than 2000 twins • Why is there such a great variation in naevi number in Caucasian populations? • Why do genes disappear with age?
Naevus and ageing • It had been noted in our research in familial melanoma that patients with multiple atypical naevi were less likely to have sun damage • Less wrinkles, less solar lentigines and fewer solar keratoses • What is the significance of this?
Telomeres • Telomeres-DNA sequence at the end of telomeres • Non coding DNA • Biological clock which shortens with age • The speed of telomere shortening with age varies between individuals which is in part genetically determined • Smoking, obesity and chronic diseases can shorten telomere further
Theory of antagonistic pleiotropy • p53 (“Guardian of the genome”) • Skin cancerogenisis Versus skin ageing (cell senescence)
Naevus marker of reduced senescence • Naevus may therefore be a good marker of reduced ageing • This may be relevant for tissues other than skin and we are now looking at bones and other tissues • This may explain why large number of naevi has remained such a common trait in the normal population • May provide a survival advantage in the selective gene pool
Vit D and sun exposure • Is Vitamin D deficiency relevant? • Vitamin D protects against osteoporosis, cancer, inflammatory and autoimmune disorders • 1400 Caucasian females: 10% had Vit D serum levels below 30 nmol/L • Skin type 1 and 2 more prone to Vit D deficiency • Vitamin D may also increase melanoma survival • Need to be more cautious when recommending sun avoidance