Acquired melanocytic nevi

Question 1

Junctional melanocytic MN: T ese arise atthe

Answer 1

dermal epidermal junction

intraepidermal

Question 2

Compound MN: Nevus cells invade the

and found in what layer

Answer 2

pap- illarydermis,andnevuscellnestsarenow oundbothintraepidermallyanddermally

Question 3

T ese represent the last stage
o the evolution o MN. “Dropping o ” into the dermis is now completed, and the nevus grows or remains intradermal (Figs. 9-1B and 9-4). With progressive age, there will be gradual brosis

Answer 3

dermal mn

Question 4

all nevus cells are now in the dermis and have lost the capacity to produce melanin

are thus skin-colored, pink, or only slightly tan. As they still grow and expand into the dermis, they li t the lesion upward and are thus usually dome-shaped or papillomatous.

Answer 4

dermal mn

Question 5

describe the diff mns. age wc it develops

Answer 5

Purelyder- mal MN are there ore almost always without pigment.Inasimpli edmanner,theclinical appearanceo MNalongthisevolutionary
path can be characterized as ollows: junctional MN is at and dark, compound MN is raised anddark,anddermalMNisraisedandlight.
T is evolution also re ects the age at which the di erent types o MN are ound. Junctional and compound MN are usually seen in child- hood and through the teens, whereas dermal MNstartmaniestinginthethirdand ourth decade.

Question 6

junctional mn lesion

Answer 6

Macule,oronlyveryslightlyraised (Fig.9-2).Uniormtan,brown,darkbrown,or even black. Round or oval with smooth, regular borders. Scattered discrete lesions. Never >1cmindiameter;i

Question 7

lesion of compound melanocytic nevi

Answer 7

LESIONS Papules or small nodules (Fig. 9-3). Dark brown, sometimes even black; dome- shaped, smooth, or cobblestone-like sur ace, regular and sharply de ned border, some- times papillomatous or hyperkeratotic. Never >1cmindiameter;i >1cm,themoleisa congenitalnevomelanocyticnevus,aDN,or a melanoma. Consistency either rm or so . Color may become mottled as progressive conversion into dermal MN occurs. May have hairs

Question 8

lesion of dermal mn

Answer 8

Sharplyde nedpapuleornodule. Skin-colored, tan, or ecks o brown, o en with telangiectasia. Round, dome-shaped (Fig. 9-4), smoothsurace,diameter<1cm.Usuallynot present be ore the second or third decade. Older lesions, mostly on the trunk, may becomepedunculatedanddonotdisappear spontaneously. May be hairy.

Question 9

indication for removal

Answer 9

Indications or removal o acquired melano- cyticMNarethe ollowing:
Site: Lesions on the scalp (only i dif cult to ol- low and not a classic dermal MN); mucous membranes, and anogenital area.
Growth:I thereisarapidchangeinsize. Color:I colorbecomesvariegated.
Border:I irregularbordersarepresentorde-
velop.
Erosions:I lesionbecomeserodedwithout
major trauma.
Symptoms:I lesionbeginstopersistentlyitch,
hurt, or bleed.
Dermoscopy:I criteria ormelanomaoradys-
plastic nevus are present or appear de novo

Question 10

Spitz nevus is a benign, dome-shaped, hairless, small (< 1 cm in diameter) nodule, most o ten pink, red,ortan(Fig.9-9A).Thereisotenahistoryo recentrapidgrowth.
■ Incidence is 1.4:100,000 (Australia). It occurs at all ages but a third o the patients are children
< 10 years; rarely seen in persons ≥ 40 years. Lesions arise within months. They are papules, dome- shaped, relatively f at nodules, round, well-circumscribed, smooth-topped, and hairless. They are a uni orm pink-red (Fig. 9-9A), tan, brown, dark brown, or even black (Fig. 9-9B); are rm; and usually distributed on the head and neck.
■ Di erentialdiagnosisincludesallpink,tan,ordarklypigmentedpapules:pyogenicgranulom,hem- angioma,molluscumcontagiosum,juvenilexanthogranuloma,mastocytoma,dermato broma,MN, DN (amelanotic), and nodular melanoma.
■ Dermatopathology:Hyperplasia o the epidermis and melanocytes and dilation o capillaries. Admixed large epithelioid cells, large spindle cells with abundant cytoplasm, and occasional mitotic
gures.
■ Histologic examination must be done to con rm the clinical diagnosis. Excision in its entirety is
importantbecausetheconditionrecursin10to15%o allcasesinlesionsthathavenotbeen excised completely. Spitz nevi are benign, but there can be a histologic similarity to melanoma and the histopathologic diagnosis requires the help o an experienced dermatopathologist.
■ Spitz nevi do not usually involute, as do common acquired MN. However, some lesions have been observed to trans orm into common compound MN, whereas others undergo brosis and in late stagesmayresembledermato bromas.
■ Synonyms: Pigmented and epithelioid spindle cell nevus. Decades ago, these were called “juvenile

Answer 10

spitz nevus