Pathology Of Pigmented Skin Lesions Flashcards

1
Q

Where do melanocytes migrate from the neural crest to?

A

Skin
Uveal tract
Lepitomeninges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What gene determines the balance of pigment in skin and hair?

A

MC1R

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What pigment causes red hair?

A

Phaeomelanin
Eumelanin causes every other hair colour
MC1R turns phaemelanin into eumelanin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a freckle (ephilides)

A

Clumpy distribution of melanocytes

One defective copy of MC1R

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an actinic letinges?

A

Age or liver spots related to chronic UV exposure

Found on face, forearms and dorsal arms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Histologically what do actinic letinges look like?

A

Epidermis elongated rete ridges

Increase melanin and basal melanocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a melanocytes naevus?

A

Benign melanocytic tumour that contains nevus cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do naevus develop?

A

Junctional naevus in childhood - melanocytes proliferate to clusters of cells at the DEJ
Compound naevus in adolescence - junctional cluster and groups of cells in dermis
Intradermal naevus in adulthood - all junctional activity has ceased, entirely dermal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does a dysplastic naevus look like?

A

Generally over 6mm in diameter
Variegated pigment
Border asymmetry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a sporadic dysplatic naevus?

A

Not inherited
One to several atypical naevus
Risk of MM slightly raised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a familial dysplastic naevus?

A

Strong FH of melanoma
Autosomal inheritance with high penetrance
Lots and lots of atypical naevi
Lifetime risk of melanoma is 100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do dysplastic naevi look like histologically?

A

Architectural atypia and cellular atypia
Host reactoin-fibrosis and inflammation
Epidermis not effaced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a halo naevi?

A

Peripheral halo of depigmentation around naevus dude to lymphocytes attacking melanocytes in naevus causing regression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are blue naevi?

A

Entirely dermal and consist of pigment rich dendritic spindle cells
Cellular variant may have mitosis and mimic melanoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a spitz naevus?

A

Benign juvenile melanoma
Consist of large spindle elitheliod cells
Mimics melanoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the epidemiology of MM?

A

Commoner in females
Rare in childhood
Incidence peaks at middle age

17
Q

What is the aetiology of MM?

A

Sun exposure in childhood
Multifactorial
Most common on sun exposed sites - scalp, face, neck, arm, trunk, leg

18
Q

When should melanoma be suspected?

A
Change in shape
New pigmented lesions in adulthood
Irregular pigmentation 
Bleeding
Development of satellite nodules
Ulceration
19
Q

What are the different types of melanoma?

A

Superficial spreading - trunk and limbs
Acral/ mucosal
Lentigo maligna - sun damaged face/neck/scalp
Modular - trunk

20
Q

What are the different growth phases of MM?

A

Grow as macules when either entirely in situ or with dermal microinvasion - RGP
Melanoma cells will invade the dermis an expansile mass with mitosis - vertical growth phase

21
Q

What is the growth of nodular MM?

A

No clinical or microscopic evidence of RGP
Simply a nodule of VGP tumour
Very aggressive

22
Q

What is breslow thickness?

A

Deepest tumour from granular layer in millimetres

23
Q

What are the different breslow depths and survival rates at 5 years?

A
pTis - 100% survival
pT1 - < 1mm 90% survival 
pT2 - 1-2mm 80% survival 
pT3 - 2-4mm 55% survival
pT4 - >4mm 20% survival
24
Q

What are the breslow terms for ulceration?

A

Suffix b indicates tumour ulceration - pT3b

25
What is satellite spread of MM?
Local dermal lymphatics
26
Where are malignant melanomas likely to spread?
GI tract Brain Lungs
27
How is melanoma treated?
Primary excision to give clear margins Sentinel node biopsy - if positive perform regional lymphadenectomy Chemo, immunotherapy, genetic therapies
28
What mutations do acral melanomas tend to have and how can they be treated?
C-kit treated with imatinib
29
What mutations do melanomas arising from intermittently sun exposed skin tend to have?
BRAF