9a - Nevi & Malignant Melanoma Part 1 Flashcards
What is a nevus?
Mole
What are the ABCDEs of examining a mole?
Asymmetry Border irregularity Color variation Diameter (size/enlargement) Evolving (change in size, shape, color or a new lesion)
Melanocytic nevus are also known as:
Moles
What are melanocytic nevi?
Benign tumors composed of nevus cells derived from melanocytes
Incidence and distribution of melanocytic nevus?
Both sexes
Become larger during 50’s and 60’s
Anywhere, but typically found in sun exposed areas
Morphology of melanocytic nevus
Sharply circumscribed Uniform colored papules or macules Irregular surface with or without hair Single or multiple Size varies greatly
Dx of melanocytic nevus?
Appearance and history
Bx reveals nest of nevus cells
Bx any lesion if change in appearance
Txt for melanocytic nevus
Follow-up for ABCDE changes
If >100 nevi, follow at 6-12 month intervals
Surgical excision for shady shit
What are the three main subtypes of common (acquired) nevi?
Junction nevi
Compound nevi
Dermal nevi
Progress over years, affected by hormones and sun
Slide 8
Illustration of development of nevi over the years
Junctional nevi
Nest in the epidermis and epidermis-dermal junction
Flat or slightly elevated
Light brown to brown-black with uniform pigmentation
Size <0.5-0.8cm
Most common in childhood - may develop into compound nevi after childhood
Compound nevi
Nevus with nest into the upper dermis
Slightly elevated to dome-shaped, smooth or warty surface, with or without hair
Uniformly round, oval, and symmetric
White periphery = “halo nevus”
Dermal nevi
All nevus cells in dermis, sometimes in fat cells
Dome-shaped (MC), verrucous, pedunculated, sessile
Skin colored to brown-black with hair, become lighter with age
Common in grown-ups
What are congenital melanocytic nevi?
Found at birth - 1-6% of all newborns
Vary in size from <1cm to >20cm
Most grow proportionally with child
Greater risk of malignant transformation if >5 BSA or >20cm
Management of congenital melanocytic nevi?
Small? Leave alone
Medium? Remove after puberty
Large? Increased incidence of MM; even with removal, 2-3% overall MM risk
What is nevus spilus?
AKA “speckled lentiginous nevus”
MC in adolescence
Hairless, oval or irregularly-shaped brown macule
Dotted with darker brown to black papular spots
ANYWHERE, not related to sun exposure
Txt - nothing
What is Becker’s nevus?
Either a brown macule, a patch of hair, or both (NO nevus cells) (but it’s still called a nevus….)
Where is Becker’s nevus found?
MC’ly unilateral upper back, shoulder, upper arm, submammary
What is Becker’s nevus syndrome?
Presence of BN plus associated with ipsilateral breast or limp hypoplasia, scoliosis, spina bifida occulta
Txt for Becker’s Nevus?
Usually too large to excise
Hair may be shaved or permanently removed
Laser tx for removal of hair and pigmentation
What is the Halo Nevus?
Compound or dermal nevus that develops a white border
MC in adolescence
May herald onset of vitiligo
Morphology of Halo Nevus?
One or more hypopigmented to white lesions that contain a central red, brown, or black nevus
No melanocytes in the halo
Nevus regresses and pigment returns (occurs over a decade or more)
Where are Halo Nevi most commonly found?
On the trunk
*never on the palms / soles
Txt for Halo Nevi?
Teens - none needed (tho parents may push for excision)
Adults - Wood’s lamp - look for blue vitiligo - bx if suspect MM
