Melanocytic naevi and Melanoma Flashcards
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Freckling inherited as autosomal dominant trait
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onset age 5 ish
MC1R gene mutation may lead to freckling
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freckles, CALMs and vulval/penile/oral melanosis all have increased melanin production but no increase in number or distribution of melanocytes
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In vulval melanosis may be slight increase in number of melanocytes esp in larger, darker lesions.
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Lentigines have increased melanin production but no increase in number or distribution of melanocytes
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In lentigines the number of melanocytes is often increased
melanocytes remain limited to basal layer
Solar lentigo may or may not have increased melanocyte numbers
Melnaocytes are usually normal in appearance but PUVA lentigines have large melanocytes with mild cytological atypia
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Freckles are independent risk factor form melanoma
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people with many freckles are more than twice as likely to get a melanoma
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freckles and lentigines fade with time out fo the sun
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freckles do lentigines may fade a little but tend to persist
CALMs do not change
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Freckled people have more naevi
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What are Rx for freckles?
Sun protect
IPL first line about 3 treatments
QS 532nm (freq doubled Nd:YAG) laser - end point is even frosting
Can use ablative or fractionated laser – fractionated probably better esp erbium
35% TCA peel
2-4% hydroquinone in morning and retinoic acid in evening and high SPF (UVA blocking) sunscreen
Gentle cryotherapy
What syndromes are associated with freckles?
XP NF (trunk, axilla, groin - Crowe's sign) Progeria LEOPARD Moynihan’s syndrome (HOCM + LEOPARD)
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Regarding CALMs
10-20% of normal population have one
1% of normal population have up to 3
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Rare to have more than 3 unless part of a syndrome
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CALMs are rare in afro-caribbeans
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more common
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In CALM there are usually fewer melanocytes than in surrounding normal skin
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but increased melanin production
What syndromes are assoc w/ CALMs?
Cheer leader with CALMs spins the BATANS
Bloom’s syndrome
Albright (McCune-Albright) syndrome (coast of Maine)
Tuberous sclerosis
Ataxia telangiectasia
NF1
Silver-Russell (Russell-Silver) syndrome
Also; Idiopathic NF1-like syndrome (Legius syndrome) NF2 Watson syndrome (Allelic to NF1) Noonans syndrome LEOPARD syndrome (cafe noir), Moynihan's Carney complex (cafe noir) Fanconis anaemia Gorlin’s Cowdens (sometimes) MEN1 (sometimes) Mafuccis Gaucher Chediak-Higashi Hunter syndrome Multiple mucosal neuroma syndrome
What syndromes are assoc w/ Cafe noir macules?
LEOPARD syndrome
Carney complex
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NF1 typically has several CALMs >15cm diameter
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but only size >15mm in adult required for diagnostic criteria
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topical skin lighteners help CALMs
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no effect
generally Rx resistant
Can try pulsed dye, QS Ruby or freq doubled Nd:YAG lasers
ablative erbium laser has also been used
variable response, high risk of recurrence
What is lentiginosis?
Lentiginosis means either many lentigines or lentigines in a specific distribution in keeping with a clinical syndrome
NB lentiginosis syndromes often also have ephelides and/or CALMs
What are the types of lentigo?
Simple lentigo (lentigo simplex) Solar lentigo (=senile lentigo) + variants; - Ink spot lentigo - PUVA lentigo Scar lentigo
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Solar lentigo can evolve into lichenoid keratosis or reticulated seb K
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Xeroderma pigmentosum is associated with many CALMs
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Many ephelides and solar lentigines
What are treatments for solar lentigo?
simialr to freckles but topical whiteners rarely effective
Sun protect
QS 532nm (freq doubled Nd:YAG) laser - end point is even frosting - 1st line treatment
IPL – may need up to 5 Rx at monthly intervals
35% TCA peel
Gentle cryotherapy - C tip spray; 3-5secs from 2cm
Can use ablative or fractionated laser – fractionated probably better esp Erbium
PUVA lentigo occurs in 90% of pts treated with PUVA
False
50%
More develop if – receive more treatments, older age, male sex
Fewer develop in darker skin phototypes
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PUVA lentigines can occur on any skin exposed to PUVA regardless if normally sun exposed or not
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PUVA lentigines occcur early during PUVA Rx
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usually after 5-7 yrs of Rx
Persist for years after PUVA stopped
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PUVA lentigines are a marker for increased risk for PUVA-related malignancy
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PUVA lentigines are darker and more stellate appearance than solar lentigines
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look more like simple lentigo than solar lentigo
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lentifo simplex is more common in darker skin types
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simple lentigo may be present at birth or appear shortly after birth
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simple lentigo of the nail matrix are a common cause of longitudinal melanonychia
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simple lentigo is a brown-black homogenous pigmented macule. usually
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Acral pigmented lesions are most often lentigo simplex histologically
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What is Generalized lentiginosis (syndrome)?
Multiple lentigines appearing singularly in small crops from infancy onwards
No known cause or association
What is Eruptive lentiginosis (syndrome)?
Rare, widespread development of numerous lentigines over months-years
Adolescents and young adults
No systemic illness/associations
What is Unilateral (zosteriform/segmental) lentiginosis (syndrome)?
Lentigines appearing on one side of the body during childhood
May be zosteriform appearing in dermatome like distribution – often naevoid
May be associated neurological abnormalities – usually not in zosteriform cases
2-10mm lentigines clustered without background hyper pigmentation as seen in naevus spillus
What is Centrofacial lentiginosis?
Very rare poorly defined triad;
Lentigines limited to medial face
Neuropsychiatric problems
Dysraphic anomalies
AD inheritence
Small black/brown macules appear in infancy in horizontal band across central face
Also; coalescence of eyebrows, high-arched palate, absent upper median incisors, spina bifida, sacral hypertrichosis & scoliosis
Frequent learning difficulties and epilepsy
What is Laugier-Hunziker syndrome?
Rare acquired lentiginosis syndrome onset in adulthood, benign cause unknown
Macular pigmentation of lips and buccal mucosa, palms and soles
Longitudinal black melanonychia
No systemic associations, good prognosis
DD for Peutz-Jeghers
Which lentiginosis syndromes have pigment change only with no systemic features?
Generalized lentiginosis
Unilateral (zosteriform/segmental) lentiginosis
Eruptive lentiginosis
Inherited patterned lentiginosis in black people
Laugier-Hunziker syndrome
NB Dowling-Degos and variants can look like lentigines but often look more reticulate and may be hypopigmented/erythematous
Which lentiginosis syndromes have pigment change with systemic features?
Centrofacial lentiginosis Cronkhite-Canada syndrome Carney complex Peutz-Jeghers syndrome LEOPARD syndrome all AD except Cronkite-Canada (acquired, cause unknown)
Mucosal melanotic macules, mucosal melanosis or mucosal lentiginosis are all the same thing
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Mucosal melanosis is common and usually benign
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but vulval melanosis is seen in middle aged women (esp early 40s)
- if occurs in older women think of melanoma even if multifocal
- if occurs in children think of lentiginosis or similar syndromes;
Peutz-Jeghers
Carney complex
LEOPARD
Bannayan-Riley-Ruvalcaba
Dowling-Degos
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smoking, trauma and inflammatory demratoses can trigger mucosal melanosis
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mucosal melanosis is pre-malignant
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also No proof that melanosis is a risk factor for melanoma
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Labial melanotic macules are most common on the lateral parts of the lip
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Most commonly central 1/3 of lower lip, ?due to UV
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Vulvar melanoma is the most common vulval cancer
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2nd most common after SCC
10% of vulval cancers
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Vulval bleeding, pruritus, discharge, irritation or lymphadenopathy can ll be due to vulval melanoma
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take these serious;y and examine carefully
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Molecular typing of vulval melanoma is more like acral melanomas than cutaneous ones
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KIT gene is most common mutation – up to 35% of cases
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radical vulvectomy is performed for vulval melanoma
False
treat simialrly to skin melanoma
WLE is best if possible
vulvectomy rarely indicated
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Vulvar naevi arise in younger women than melanosis or melanoma
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naevus - late 20s, early 30s
melanosis - 40-44yrs
melanoma - 40-70 or older
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Vulvar naevi occur in 20% of adult women
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2%
account for 23% of all pigmented vulvar lesions
arise on lab maj, lab min or clitoral hood
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Atypical Melanocytic Naevi of Genital Type (AMNGT) are generally seen in slightly younger women
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can be children and teens
more often on lab min and on mucosal parts esp in girls under 10
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Atypical Melanocytic Naevi of Genital Type (AMNGT) account for 5% of vulval naevi
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may be large, irregular, darkly pigmented. May have personal or FHx of dysplastic naevi or melanoma
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Atypical Melanocytic Naevi of Genital Type (AMNGT) ae pre-malignant lesions
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Both vulval naevi and AMNGT appear to have benign behaviour
AMNGT is a special site naevus - may have focal pagetoid, cytological atypia and rare mitoses
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most vulval melanomas arise from a naevus
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Vulval melanomas on mucosal and border of mucosal and hairy skin rarely have a benign naevus associated (2%)
35% of melanomas on hairy vulva may arise from a naevus
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Both vulval melanosis and AMNGT can arise on a background of vulval lichen sclerosus
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but LS not a risk factor for vulval melanoma
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In first 1-2 years of life infants may develop acquired naevi which clinically and histologically resemble congenital naevi
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‘congenital naevus tardive’
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Congenital melanocytic naevi (CMN) are present in up to 12% of newborns esp Asian and black skin
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2%
and 2% of adults have lesions resembling congenital naevi which may or may not be truly congenital
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Congenital melanocytic naevi are due to a postzygotic mutations in BRAF gene
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NRAS gene
type of mosaic RASopathy
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There is a higher risk of melanoma in congenital naevi >10cm diameter when an adult
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What is the calssification of CMN?
Small less than 1.5cm medium/large 1.5-19.9cm large/giant 20cm and over - based on adult diameter attained some call naevi >40cm diameter ‘garment naevi’
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Naevi >9cm on scalp in adults are considered giant
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Also naevi >6cm on the body in neonates
size grows in proportion with child
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Giant/garment naevi in lumbosacral region often called ‘bathing trunk’ naevi
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Bathing trunk naevi usually cover lower back, buttocks and extend to thighs
75% also have many satellite naevi and develop more with time esp in first 2 years. These can be at distant sites to the main naevus
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Most congenital naevi are in small category
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Congenital melanocytic naevi dont change in appearance with age, only in size
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Many become more pale in first 2 years
can become thicker in childhood
Surface often becomes thick/rugose or warty - esp on scalp; simulates cutis verticis gyrata
Often also develop nodules within larger naevi
Can be increased terminal hair in naevus skin esp on scalp – hair often dark, thick and wiry
What are the associations of CMN on the skin?
Absence of subcut fat and muscle mass under the naevus is most common and can cause discomfort in naevi over the sacrum etc Atopic dermatitis Perineavic leukoderma Neurofibromatosis – up to 5% of NF pts have a CMN CALMs Mucosal naevi (30%) Infantile haemangioma can be part of epidermal naevus syndrome Benign nodules Plexiform-like overgrowths Fascicular schwannoma Lipoma Lymphangioma Fibroepithelial polyp Ectopic Mongolian spot Neurilemmoma Cartilaginous hamartoma
What are the non-skin asociations of CMN?
Limb hypertrophy (22.5%) club foot, atrophy or hypertrophy of musculoskeletal structures esp under naevi on limbs
EEG abnormalities (20%)
CNS symptoms due to neuro melanosis
Rasopathy induced hormonal disturbances;
- Higher BMI compared to normal due to increased adiposity
- Premature thelarche (breast development) 3%
- Cryptorchidism 6%
What is neurocutaneous melanosis?
Neurocutaneous melanosis = neuromelanosis associated with a CMN
Usually giant CMN or multiple smaller lesions
Involvement of nervous system by melanocytic proliferation – can be amygdala, cerebrum, cerebellum, midbrain, pons, medulla, meninges or spinal cord
Present before age 3 in most cases; often before or around age 2;
2nd peak in teens-20s
Complications rare but can cause raised ICP, hydrocephalus, spinal space-occupying lesions
Risk if CMN overlying spin – meningeal involvement, spina bifida, meningocele, tethered spinal cord, pits, lipoma
Can develop melanoma in skin lesions or in neuromelanosis but not in both
What are the histo features of CMN?
Dermal or compound type melanocytic naevi with naevus cells extending more deeply into dermis
Often naevus cells involve appendages and can extend into fat and muscle
Naevus cells may be arranged in ‘splaying’ pattern AKA single file or ‘Indian filing’
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In CMN Naevus cells start higher up and go deep in first months of life
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so no benefit from early dermabrasion or similar
What investigations should be performed for CMN?
T1 weighted MRI of brain if want to look for neuromelanosis – some advocate screening if giant CMN; some advocate only investigating if symptoms as there is no curative Rx
MRI may be more accurate if performed before 4 months
Cannot predict which neuromelanosis cases will cause symptoms and which will be assymptomatic
MRI all pts if CMN overlies spine – can treat tethered cord with surgery but cannot sure after it becomes symptomatic
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nodular melanoma is most common type to arise from CMN
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superficial spreading
but arise from dermal portion making diagnosis difficult
Higher risk of presenting with mets and unknown primary
What are the complications of CMN?
Melanoma - 5-7% of giant CMN pts get melanoma by age 60
Nodular proliferative neurocristic hamartoma – tumour derived from neural crest, may be present at birth, often on scalp, benign but can turn into melanoma
Nodularities caused by proliferation of epiphelioid melanocytes – simulate melanoma
Pts w/ giant naevi can develop extracutaneous melanoma – CNS, retroperitoneum etc
Other malignant tumours (rare) – malignant blue naevus, neurogenic sarcoma, fibrosarcoma, leiomyosarcoma, rhabdomyosarcoma, neurosarcoma, osteogenic sarcoma, liposarcoma
Psychological – behavioural and emotional problems, bullying
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In CMN there is No clear evidence that removal of the naevus has any effect on melanoma risk
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symptomatic neurocutaneous melanosis has a poor prognosis
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dont excise their naevi as unnecessary morbidity
What are the treatment options for CMN?
Monitoring only - photos and FSE every 6-12 months lifelong
complete excision if small
staged excison with graft/flap repair
Partial thickness treatment options – remove some naevus cells but often not satisfactory;
- Dermabrasion– done in 1st 6 months of life when cleavage plane exists between naevus and underlying tissue
- Dermatome shaving
- Chemical peel
- Curettage – done in 1st 6 months of life when cleavage plane exists between naevus and underlying tissue
- Cryotherapy
- Electosurgery
- Pigment laser – QS; Ruby, Alexandrite, Nd:YAG
- Ablative laser – CO2 or Erbium:YAG
- XRT – described but least useful option and high risk AEs
which syndromes are associated w/ naevus spillus?
phakomatosis pigmentovascularis (type 3+4)
phakomatosis pigmentokeratotica
Rare speckled lentiginous naevus syndrome – naevus + ipsilateral dysaesthesia, muscle weakness and hyperhidrosis
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Speckled and lentiginous naevus has a small increased risk of melanoma
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Unlike the individual lentigines and junctional naevi within a naevus spillus, the background hyperpigmentation has normal melanosyte numbers
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subtle increase in melanocytes in background lesion in lentiginous arrangement
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90% of naevi are junctional in childhood
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get some new naevi up until around mid 40s then begin to involute
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Number of naevi is mainly genetically determined
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small effect of sun exposure esp if intermittent
What things can trigger development of new naevi?
Sun exposure esp multiple or severe sunburns
Skin injury – SJS/TEN, EB, LS
Immunosuppression inc drugs and AIDS, BMT
Hormones - Pregnancy, growth hormone, addisons Dx, thyroid hormone, afamelanotide (αMSH analogue)
Sorafenib (kinase inhibitor)
EB naevi which develop at blister sites maybe up to 3cm diameter - Should observe but no reports of melanoma developing
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A persons overall number of naevi is single biggest risk factor for melanoma
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Renal transplant pts have fewer naevi
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more
Childhood leukaemia survivors also have more than ave naevi and inc risk of melanoma
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Eczema pts often have fewer naevi than average
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Balloon cell melanoma does NOT arise from balloon cell naevi
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In acral melanocytic naevi some degree of architectural atypia (including Pagetoid spread) and cytological atypia is normal
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What are the dermoscopic patterns of naevi on feet?
Fibrillar – in friction prone, wt bearing parts
Classical groove pattern – seen in peri-wt bearing areas
Lattice pattern – seen on the arch
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conjunctival naevi are more risky than skin naevi
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behave the same
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Nail matrix naevi present as longitudinal melanonychia
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It is common for melanocytes in IDNs to become spindle shaped (neuroid)
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What is Sutton’s naevus
Halo naevus
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In older adults a sudden onset of multiple halo naevi can indicate a melanoma of the skin, eye or elsewhere
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What are the stages of change in halo naevus?
4 stages; 1 – central brown naevus 2 – central pink naevus 3 – depigmented macule only remains 4 – repigmentation of macule