Pigmented Lesions

Telling the good from the bad

ICGP Summer School 2011

Benign Skin Lesions – origins. ORIGIN

LESION

Melanocyte

Ephelides – freckle. Solar lentigine – liver spot. Congenital melanocytic naevus. Acquired melanocytic naevus – junctional,compound,intradermal, halo,spitz,atypical,blue.

Keratinocyte

Seborrhoeic keratosis. Actinic keratosis.

Hair follicle

Epidermoid cyst.

Fibroblast

Dermatofibroma.

Blood vessel.

Spider naevus. Angiokeratoma – Campbell de Morgan spot. Pyogenic granuloma. Haemangioma.

Malignant Melanoma 600 diagnosed annually. 60% female, 60% < 65 years. 2020 projected 1,250 new cases/year. Third most common cancer in the 15-44 years age group.

Diagnosis Systematic approach – Hx and Ex. Avoid spot diagnosis. Change in youth – usually benign, > 35 years, may be sinister. Aids – magnification lens, SLR digital camera, dermatoscope.

Freckles and Lentigines

Ephelide - freckle. • 1 to 3 mm. • Light to dark brown. • Skin type 1 and 2. • Independent risk factor for MM.

Freckles Normal numbers of melanocytes - produce more melanin than usual. Blue eyed, fair skinned, red hair - tendency to burn but not tan. Most numerous after the age of 5 years and fade > 20 years. Darken on sun exposure.

Not premalignant but indicate skin type at increased risk of developing skin cancer, including melanoma.

Lentigine Large freckle - increased number of melanocytes. Brown or blackish macules - sometimes since birth.

Lentigines

Any part of the body.

Solar lentigines develop in the over 40’s - sun exposed skin - chronic UV damage.

No malignant potential.

Solar Lentigine - Management. • High factor sun block – may regress. • Cryotherapy. • Larger,variable colour,solitary – biopsy to o/r lentigo maligna.

Moles (Melanocytic Naevi)

Only 30% of melanomas arise from moles. 70% in normal skin.

Naevi derived from melanocytes. Congenital Melanocytic Naevus

Small, Medium Giant. Acquired Melanocytic Naevus Junctional Melanocytic Naevus Compound Melanocytic Naevus Intradermal Melanocytic Naevus

Halo Naevus Spitz Naevus Blue Naevus Atypical Melanocytic Naevus

Congeni t al mol es Small < 1.5cm.

1%.

Medium 1.5 - 20 cm.

0.6%

Large > 20cm (Larger than the baby’s palm at birth >6cm).

1/20,000.

Congeni t al mol es Almost all melanomas arising in congenital moles do so in large ones (5%). Most melanomas arise before puberty (age of 2 to 3 years). Adults with congenital moles at very low risk indeed.

Acquired Moles

Dyspl ast i c ( At ypi cal ) Mol es Di f f er f r om or di nar y mol es • Larger. • Irregular border.

Therefore more difficult to tell from melanoma clinically

• Irregular colour. • Different histology.

And histologicaly

Atypical (Dysplastic) Naevus Common upper back - also scalp, female breasts, feet, hands, irises, buttock. Start teenage years - develop throughout life.

Surgical excision of an atypical naevus is only justified if an expert is unsure of the diagnosis.

Both banal acquired and dysplastic naevi -> increased risk melanoma Only 26% of melanomas had a contiguous nevus (57% were nondysplastic) One estimate suggests only 1 in 10 000 dysplastic nevi per year will transform into melanoma.

Dermoscopy has unequivocally improved the diagnosis of melanocytic lesions - improvement in the sensitivity for the diagnosis of melanoma (ie, the correct diagnosis of true melanoma)

Much weaker improvement in specificity (ie, the correct diagnosis of true nonmelanoma) Specificity improved by evaluating lesions in the context of other nevi from the same patient (comparative approach) Nevus that does not fit within the overall repetitive nevus pattern on an individual - “ugly duckling sign” considered suspect, regardless of its appearance

Atypical Naevus Syndrome 2% population.

Features of Atypical Naevus Syndrome • • • • • •

100 or more melanocytic naevi. More than two atypical naevi (≥5 mm). Naevi on sites such as breasts in females, buttocks, scalp, ears, dorsum of feet. New naevi develop until late in life. Tend to develop melanoma at an early age. Increase risk of multiple primary melanomas.

Risk of melanoma increases with increasing numbers of atypical naevi and especially so if a family member has a history of melanoma i.e. FAMM (familial atypical molemelanoma) syndrome.

Melanoma – Ri sk f act or s. • RISK FACTOR

• RELATIVE RISK

High density freckles.

2

Red hair.

3.5

100 moles.

7

5 atypical moles.

6.5

Higher social class.

3

Regular sunbed use, starting < 35 yrs.

1.7

Spitz Naevus (Tumour) Characteristic histology – spindled and epitheloid melanocytes. Uncommon, any age (most common < 25 years).

Spitz Naevus • Rapid growth at onset – then slow. • Face/extremities mostly. • ? Compound naevus. • Typical and atypical spitz naevi may be confused with melanoma. • All should be excised. • Spitzoid melanoma = melanoma with Spitzoid features.

Spitz Naevus Solitary, well-circumscribed, dome shaped papule/nodule, < 1cm diameter. Pink, tan, brown. Face, neck, thigh.

Spitz Naevus – Management in Children < 12 years, rare after 40 years. < 1 cm. No atypical (clinical or dermoscopy) features. Observation 6 monthly.

Blue Naevus • • • •

Macule, plaque or papule. Head/neck, dorsum hands/feet, sacral area. Dark blue. ? Melanocytes not completed migration to dermoepidermal junction – in the dermis. • More common Asian ethnicities.

Naevus Spilus (Speckled lentiginous naevus) • Uniformly tan to start with. • Macular/papular areas develop (Speckles).

• Tan area = lentigo. • Speckles = acquired melanocytic naevus. • Common – 2%.

• Present first year of life. • Melanoma risk – especially if > 20cm.

ABCDE Rule • Asymmetry – one half of lesion unlike the other. • Border irregular – scalloped or poorly defined. • Colour variety – from one part of the lesion to another. • Diameter > 6 mm. • Evolution.

Increasing incidence – r eal or appar ent ?

 ? Earlier diagnosis.  Much of rising incidence is probably real.

MELANOMA IF DETECTED EARLY AND EXCISED IS MAINLY CURABLE.

Mel anoma yT pes Superficial Spreading MM

80%

Nodular MM

10%

Lentigo Maligna MM

5%

Acral MM

5%

Suspicious Lesions

• Older patient. • Irregular outline. • > 3 colours.

Treatment of Malignant Melanoma

Surgery

Relationship Between Dept of Invasion and Survival for Melanoma Dept of Invasion

10 year survival rate

In situ

100%

< 0.85mm

95.7%

0.85 – 1.69 mm

87.1%

1.70 – 3.59 mm

66.5%

> 3.6 mm

46%

MELANOMA IF DETECTED EARLY AND EXCISED IS MAINLY CURABLE.

Seborrhoeic Keratosis – Basal Cell Papilloma. • • • •

“ barnacles on a rusting hull” 2mm to 3 cm. Yellow, brown, black. Dermatoscope – keratin plugs and comedones. • Management – curettage, cryotherapy – if irritated or unsightly - must be sure of diagnosis.

Pigmented AK

Looks like lentigo maligna but feels like actinic keratosis

Dermatofibroma – Histiocytoma. • • • •

Lower limbs especially. Firm, persisting nodule. Dimpling – on presure from the side. Surrounding pigmentation.