3 - Derm - Benign and Malignant Melanocytic Lesions - Moles (naevi)

Question 1

differences between acquired and congenital naevi

Answer 1

acquired - usually appear before 25 - progress through stages 1-3 over time

congenital - at birth, 1% of newborns

Question 2

Acquired naevi - what causes them? when do they appear?

Answer 2

abnormal but benign proliferation of melanocytes in epidermis
appear in adolescence and early adulthood

Question 3

3 main types of acquired naevi?

Answer 3

junctional
compound
dermal

Question 4

3 other types of acquired naevi?

Answer 4

blue
atypical
halo

Question 5

junctional - appearance? where is proliferation?

Answer 5

macular and dark

at dermoepidermal junction - within epidermis

Question 6

Compound - appearance? where are melanocytes?

Answer 6

brown papules (warty)
melanocytes in epidermis and dermis

Question 7

Dermal - confused with? appearance? where?

Answer 7

only in dermis
loss of pigment, light brown to skin coloured
possible to confuse with BCC

Question 8

atypical naevi - similar to? aetiology? risk of?

Answer 8

melanoma
genetic, UV exposure
higher risk of melanoma esp if >50y/FHx

Question 9

Halo naevi - where? who? appearance + why?

Answer 9

back of young adults
white halo due to lymphocyte mediated loss of melanocytes

they are benign

Question 10

blue naevus - appearance and why

Answer 10

blue - melanocytes residing deeper in epidermis

Question 11

2 types of congenital naevi

Answer 11

giant congenital naevi

cafe au lait macule

Question 12

giant congenital naevus - appearance? risk?

Answer 12

“bathing costume naevus”

increased risk of melanoma

Question 13

cafe au lait macule - appearance? multiple can be sign of?

Answer 13

tanned macule, oval usually

multiple can be sign of neurofibromatosis