malignant melanoma
TRANSCRIPT
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.