malignant melanoma

Melanoma Precursors & Primary

Cutaneous MelanomaNurul Shuhada bt Mohd Nazari

030369

Precursor of cutaneousmelanoma

Cutaneousmelanoma

Precursor of cutaneous melanoma

• Lesions that are benign with potential of turning into malignant

1. Dysplastic Melanocytic Nevus

2. Congenital Nevumelanocytic Nevus

1. Dysplastic Melanocytic Nevus

• Atypical Melanocyte Nevus

• Acquired, circumscribed, pigmented lesion due to proliferation of atypical melanocyte

• Arise from

1. De novo

2. Melanocytic Nevi

Epidemiology

• Age & onset : children & adult

• Prevalence : 5% in white population

• Sex : equal in males and females

• Race : white. Rare in Japanese

• Transmission : Autosomal dominant

Pathogenesis

Sunlight exposure

Activation of abnormal clone of melanocyte

• Immunosuppressive patient such as renal transplant with DN have higher incidence of melanoma

• Favor part : exposed area ( eg. Back) . May also occur in covered area

Clinical Manifestation

• Duration ▫ later in childhood ▫ Do not undergo spontaneous regression

• Skin symptom ▫ Asymptomatic ▫ “Out of step” : mixture of large and small, flat and

raised, tan and very dark lesion

• Family history ▫ Family member can develop melanoma even

without DN

Note a number of lesions are of different size and color, “out of step”.Note irregularity, variegation of color which are different in the two lesions (“outof step”).

How to differentiate between DN and

other common acquired nevi?

• Larger & more variated in colour

• Asymmetrical

• Irregular border

• Characteristic histological feature

However no single feature is diagnostic

Laboratory Examination

• Dermatopathology

1. Atypical melanocyte

Hyperplasia

Proliferation disorder

2. Lentiginous pattern in basal cell layer

3. Atypical melanocyte bridging between cell layer

Management

• Surgical excision

2. Congenital Nevomelanocytic Nevus

• Congenital, clinically apparent during infancy

• Vary in size (small → large )

• Benign nevomelanocyte neoplasm

Epidemiology

• 1 % of white newborn

• Age of onset

▫ Congenital

▫ Some present after birth (tardive)

• “fading in” pattern → relatively large lesion over period of weeks

• Sex : Equal male and female

• Race : all race

Pathogenesis

• Developmental defect in neural crest-derived melanoblast

Small Giant

Distort the skin surface to some degree

Plaque with or without terminal dark brown/ black hair

Sharply demarcated

Involve majority of skin

Complete replacement of skin on back and smaller CNMN on buttock & thigh

Rugose

• Colour

▫ Light or dark brown, black.

▫ With dermoscopy, fine specking of darker hue with lighter surrounding brown hue.

• Size

▫ Small, large, giant

• Shape

▫ Oval and round

Small, variegated brown plaque on the nose. Thelesion was present at birth. Note that lesion is hairy.Congenital nevomelanocytic nevus, intermediate size.Sharply demarcated chocolate-brown plaque with sharply defined borders in an infant. With increasing age,lesions may become elevated and hairy and very discrete hairiness is also noted in this lesion

Giant CNMN

• At the head and neck

• Associated with involvement of leptomeningitiswith same pathological process

• May be asymptomatic or manifest as seizure, focal neurologic defect or obstructive hydrocephalus

• A plaque with surface distortion, covering entire segments of the trunk, extremities, head or neck.

the lesion involves the majority of the skin,with complete replacement of normal skin onthe back and multiple smaller CNMN on thebuttocks and thighs

Laboratory

• Nevomelanocyte→ well ordered cluster in epidermis

Treatment

• Surgical excision

Cutaneous Melanoma

Introduction

• Most malignant tumor of skin

• Arise from malignant transformation of melanocyte at dermal epithelial junction

• Nevomelanocyte of DN of CNMN that become invasive and metastasis after various time interval

OR

Epidemiology

• Genetic predisposition chromosome 9p21

• Sun exposure

▫ Exposure to solar radiation

Risk Factor

• Genetic markers (CDKN2a mutation)

▫ Skin type I/II

▫ Family history of dysplastic nevi or melanoma

▫ Personal history of melanoma

▫ Ultraviolet irradiation, particularly sunburns during childhood and intermittent burning exposures

• Number (>50) and size (>5 mm) of melanocytic nevi

• Congenital nevi

• Number of dysplastic nevi (>5)

• Dysplastic melanocytic nevus syndrome

Melanoma Recognition 6 signs of malignant melanoma

• A → assymmetry• B → border irregular

edges irregularly developed, sharply defined

• C → colour. Not uniform, mottled, all shades of brown, black, grey, blue, red or white

• D → Diameter. Large greater than 6mm • E → Elevation. Surface distortion

Evolving . Increase in size of lesion

4 major types of melanoma

1. Superficial Spreading Melanoma

• Commonly arise at upper back and occurs as a moderately slow-growing lesion over a period of up to 2 years

• Distinctive Morphology :

▫ Elevated, flat lesion (plaque)

▫ More striking pigment variegation

Epidemiology

• Age : 30-50 y/o

• Sex : slightly higher incidence in female

• Race : white-skinned people

• Incidence : 70 %

Pathogenesis

• Intraepidermal/ radial / early phase

▫ Tumorigenic pigment cell confined to epidermis

▫ Metastasis do not occur

• Invasive vertical growth phase

▫ Malignant cell consists of a tumorigenic nodule vertically invade dermis.

▫ Metastasis potential

In vertical growth phase

Clinical Manifestation

• Gradual darkening of one area of mole

• Change in shape

• Variegation of colour with mixes of brown, dark brown & black

• Radial to vertical growth

2. Nodular Melanoma

• Epidemiology

▫ Age : middle age

▫ Sex : equal incidence between male and female

▫ Race : all races

▫ Incidence : 15-30 %

Pathogenesis

• Same site as SSM

▫ Upper back in male

▫ Lower legs in female

• Arise from :

▫ Preexisting nevus

▫ De novo

Clinical Manifestation

• Skin lesion

▫ Uniformly elevated blueberry like nodule or ulcerated or thick plaque

▫ May become polypoid (resemble a polyp)

▫ Uniformly dark blue, black or thunder-cloud gray.

▫ Surface may be smooth or scaly, eroded or ulcerated

▫ Early lesion are 1-3 cm (may grow bigger)

Laboratory Examination

• Dermatopathology

• Appear as epithelioid, spindle or small atypical cells

• Show little lateral ( radial ) growth within and below the epidermis and invade vertically into dermis.

Management

• Surgical excision

Lentigo Maligna Melanoma

• Age : median age 65

• Sex : equal in male and female

• Race : high in white

• Incidence : 5 % of primary cutaneous melanoma

• Predisposing Factor

• Older population, outdoor occupation ( farmers, sailor, construction worker )

Pathogenesis

• LM occur on the face, neck & dorsa of forearms or hands.

• Occur almost always in older person with evidence of heavily sun damaged skin ( dermatoheliosis)

• Radial → vertical growth phase

• MIS → invasive melanoma

Clinical Manifestation

1. Gray area ( indicate focal regression ) & blue area ( indicate dermal pigment )

2. Papule or nodule

3. Other skin changes such as :

▫ Solar keratosis

▫ Freckling

▫ Telangiectasia

▫ Thinning of skin

Laboratory examination

• Dermatopathology

▫ Increase number of atypical melanocytedistributed in single layer along the basal layer

Management

• Very early lesion : Imiquimod

• Excised with 1cm beyond the clinically visible lesion

• Sentinel lymph node removal

Acral Lentiginous Melanoma

• Age : median age 65 years old

• Incidence : 7-9% in whites , 2-8% asians

• Sex : Male: Female 3:1

• Race : ALM is the principal melanoma in the Japanese (50-70%)

Clinical Manifestation

• Slow growing tumor (2.5 years)

• Appear in volar surface such as palm and sole

• ALM as subungual melanoma appear first in nail bed and involve over a period of 1-2 years.

• In vertical growth phase, nodules appear

• Area of ulceration and nail deformity and shedding of the nail may occur.