Nevi and Melanoma - Fisher

Question 1

what cell type are melanocytes derived from?

Answer 1

neural crest cells

Question 2

where can melanoma and nevi occur?

Answer 2

anywhere neural crest cells migrate

Question 3

where is the most common site for melanoma formation histologically?

Answer 3

dermal-epidermal junction

Question 4

What are the 5 general criteria for a gross diagnosis of melanoma?

Answer 4

A - asymmetry B - irregular borders C - color variation D - large diameter E - evolving/ elevated

Question 5

what is the most important factor contributing to melanoma prognosis

Answer 5

ulceration and depth of dermal involvement

Question 6

what do nevi and melanoma have in common?

Answer 6

both comprised of melanocytes, both can share mutations such as BRAF

Question 7

in general, are nevi pre-melanomas? what percentage of melanomas are derived from nevi?

Answer 7

no only 20% of melanoma develop from nevi

Question 8

how are nevi related to risk of melanoma

Answer 8

an increased number of nevi (more than 50) increase risk of melanoma

Question 9

what are the 3 types of acquired melanocytic nevi?

Answer 9

junctional, compound, intradermal

Question 10

What is this? and define

Answer 10

junctional nevus - nests of melanocytes are present within epidermis only

Question 11

what is this? and define

Answer 11

compound nevus - nests of melanocytes are present within epidermis and dermis

Question 12

what is this? and define

Answer 12

Intradermal nevus - nest of mealnocytes within dermis only

Question 13

what is the classic definition of nevus?

Answer 13

any congenital lesion of the skin - a birthmark

Question 14

2-3 mm in diameter, deeply pigmented and macular, arising at the dermal-epidermal junction above the BM - what type of nevus?

Answer 14

junctional

Question 15

3-4 mm, slightly raised, moderately pigmented, melanocytes found both intradermally and dermally - what type of nevus

Answer 15

compound

Question 16

large and dome shaped lesion, cells exclusively in the dermis - what type of nevus

Answer 16

dermal

Question 17

define halo nevi. what pt population is it more common in?

Answer 17

common acquired nevus with a surrounding zone of depigmentation common in 1st 3 decades of life, equal in males and females, more common in patients w/ vitiligo, familial tendency

Question 18

what is the etiology of halo nevi

Answer 18

highlights the relationship between melanocytic neoplasia and host immunity - body recognizes somewhere there is melanoma, starts attacking all nevi everywhere - causes clearing

Question 19

how do you classify congenital nevi?

Answer 19

according to size (small less than 1.5 cm, medium 1.5-20 cm, large more than 20 cm)

Question 20

congenital nevi classified according to size - how do you apply this classification to children

Answer 20

the number cutoffs are for adults; must adjust these numbers for neonate (know this)

Question 21

describe the clinical features of a congenital nevus

Answer 21

pigmentation varying from brown to black, grossly irregular surface, and hypertrichosis (hair is a key finding)

Question 22

for congenital nevi, what is the rule of 5s? ($$)

Answer 22

5 cm or greater, in the first 5 years of life, 5% risk of melanoma - 5 cm - this is considered large for neonate (hence the adjustment of number cutoffs)

Question 23

for atypical “dysplastic” nevi, do most pts carry an increased risk of melanoma? are dysplastic nevi precursors to melanoma?

Answer 23

no

Question 24

in what case do atypical dysplastic nevi carry an increased risk of melanoma? ($$)

Answer 24

familial history of melanoma + great numbers of atypical nevi

Question 25

what is the general clinical appearance of atypical nevi?

Answer 25

irregular borders, variegated pigment, and asymmetry - they break the ABCDE rules, and thus get biopsied b/c they resemble melanoma - but are not

Question 26

epidemiology, who is at highest risk for melanoma

Answer 26

Caucasian me older than 50

Question 27

how do melanocytes normally mature? how is this different in melanoma

Answer 27

normally - melanocytes decrease in size as they dive deeper into dermis melanoma - do not decrease in size - thus do not mature

Question 28

where do melanocytes normally reside? where would growth be abnromal?

Answer 28

melanocytes normally live in the basal layer - growth above the basal layer is abnormal

Question 29

what is melanoma in situ? what growth phase is it in?

Answer 29

unorganized melanocytes, increased in number and located above the basal layer - "radial" growth phase

Question 30

when is a melanoma capable of metastasis? how is this relevant for detection and treatment $$

Answer 30

until melanoma is located within the dermis, it cannot metastasize - find and treat early, imperative

Question 31

what is the growth phase called when a melanoma is capable of metastasis? what routes do melanoma metastasize by?

Answer 31

vertical growth phase mets via lymphatics (mainly)

Question 32

melanoma is multifactorial etiology - what 3 factors

Answer 32

genetic predisposition (BRAF) environment - UV underlying immune status

Question 33

what are the risk factors for melanoma?

Answer 33

large number of common nevi (esp more than 50) Giant congenital Nevi Atypical nevi, mostly if multiple and familial History of blistering sunburns FH of Melanoma Light Complexion, tanning bed use Underlying immune dysfunction

Question 34

ABCDE - what number is cutoff for diameter (D)

Answer 34

6 mm

Question 35

what is the ugly duckling sign in screening for melanoma

Answer 35

one lesion that stand out from all the others

Question 36

define acral lentiginous melanoma; who is it more common in?

Answer 36

melanoma on palms and soles - palmar, plantar, and subungual (under the nails) skin more common in ppl of color

Question 37

define Lentigo Maligna Melanoma; who is it more common in

Answer 37

melanoma arising on the sun exposed areas of the face in older patients

Question 38

what type of melanoma is a Lentigo Maligna variant? what does this mean for prognosis

Answer 38

melanoma in situ slow growing, still in "radial" growth phase - does not have capacity to mets - not yet

Question 39

what clinical finding heralds the progression of the in situ lesion of Lentigo Maligna to an invasive one?

Answer 39

the formation of a nodule arising in the background of a lentigo maligna - it has progressed to the dermis - vertical growth - evident by the lifting up of the skin

Question 40

define nodular melanoma; discuss the characteristic progression and what growth phase it is in

Answer 40

a black nodule arising on sun exposed skin "no preceding radial growth" - the lesion is already in the vertical growth phase (already in the dermis) at the time of presentation - has capcity to mets

Question 41

what pt population is nodular melanoma is more common in?

Answer 41

2x more in men

Question 42

what is a superficial spreading melanoma variant? what growth phase?

Answer 42

largely in radial growth phase - not nodular - but can have a nodular component can have a central nodular part, but towards the edges may only be in radial growth phase

Question 43

describe the clinical appearance of superficial spreading melanoma; what is the characteristic sign?

Answer 43

asymmetrical, irregular borders, wide variation in color, diameter more than 6 mm, elevated "red white and blue sign"

Question 44

How do melanoma usually metastasize? $$

Answer 44

lymphatics, but not exclusively (can do blood)

Question 45

what is the number one organ site for melanoma mets? $$

Answer 45

Skin

Question 46

what is the most common cause of death in melanoma? what organ involvement?

Answer 46

CNS involvement

Question 47

What is the single most important prognostic factor in melanoma? $$

Answer 47

lymph node involvement

Question 48

what are the two most important histological prognostic factors for melanoma?

Answer 48

Breslow thickness and ulceration

Question 49

define Breslow's thickness

Answer 49

distance of involvement from the stratum granulsoum (top) to the deepest tumor cell (bottom) you are measuring the depth of invasion, starting in granulosum

Question 50

what are some potential tx modalities for metastatic melanoma

Answer 50

IFNa, combination CTX, XRT, vaccine therapy

Question 51

what small molecule drug targets BRAF? what BRAF mutation in particular?

Answer 51

Vemurafenib targets V600E pt melanoma must harbor an activating mutation in BRAF V600E to approve treatment

Question 52

Answer 52

melanoma in situ

Question 53

Answer 53

melanoma in iris recall: melanocytes derived from neural crest cells, so melanomas can arise anywhere neural crest cells migrate