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Flashcards in Pathology of Pigmented Lesions Deck (32)
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1

Melanomas which appear on intermittently sun-exposed skin are most likely to have which type of mutation?

BRAF

(upregulates MEK and ERK which drive cell proliferation)

2

During embryogenesis, melanoblasts migrate to which regions of the body?

Skin (mainly)

Leptomeninges

Uveal tract

3

What are the leptomeniges?

Pia mater and arachnoid

4

Which types of melanoma grow as macules?

Acral/mucosal lentiginous

Lentigo maligna

Superficial spreading

5

What is Brelow's thickness?

The deepest part of a skin tumour as measured from the granular layer

6

Acral melanomas are associated with which mutation type?

c-kit

7

What is the MC1R protein and what is its function?

Melanocortin 1 receptor gene

Determines balance of pigment in hair and skin by converting pheomelanin to eumelanin

8

Most cases of melanoma arise ___________

Most cases of melanoma arise denovo

9

If a melanoma is invasive and >1mm thick, how should it be excised?

Excise with 2cm clearance and sentinel node biopsy

10

If a melanoma is foudn to be in-situ, how is it excised?

5mm clearance

11

What is the most common type of melanoma?

Superficial spreading melanoma

12

Where does superficial spreading melanoma normally affect on the skin?

Trunk and limbs

13

How can dysplastic naevi be described?

Naevi >6mm in diameter with varigated pigment and border asymmetry

14

Which type of naevus constits of pigment-rich dendritic spindle cells and is located in the dermis? 

Blue naevi

(benign)

15

Which type of naevus involves the destruction of melanocytes and high concentrations of lymphocytes which contribute to this destruction?

Halo naevi

16

How are halo naevi created?

Autoimmune reaction against a naevus on the skin

Lymphocytes destroy the naevus causing it to become lighter in colour, turining pink and then eventually disappearing entirely

The immune reaction destroys surrounding melanocytes which gives the halo appearance

17

Age spots are known by which other name?

Actinic lentigines

18

What are age spots due to?

Long term UV exposure

19

Where are melanocytes dervied?

Neural crest

20

For which reason do freckles occur after sun exposure?

Reflect the clumpy distribution of melanocytes in the skin

21

For freckles to be present a person requires a mutation in which gene?

MC1R (only one copy)

22

Which naevus can mimic melanoma?

Spitz naevus

23

Which may a Spitz naevus be dangerous?

Most are benign but there is a malignant variant

24

In which skin layer do melanocytes reside?

Basal layer

25

How many types of melanoma exist?

4

26

What are the four main types of melanoma?

  1. Superficial spreading
  2. Acral/mucosal lentiginous
  3. Lentigo maligna
  4. Nodular

27

Familial dysplastic naevi have which lifetime risk of melanoma?

Up to 100%

28

Which suffix in Breslow's thickness indcates ulceration?

b

29

What are the stages of Breslow's thickness?

pTis - In situ

pT1 - <1mm

pT2 - 1-2mm

pT3 - 2-4mm

pT4 - >4mm

30

What risk do large malanocytic naevi pose to becoming melanomas?

10-15%