Pathology of pigmented lesions

Question 1

Where do melanocytes originally come from?

Answer 1

neural crest

Question 2

In early embryogenesis, where do melanoblasts migrate to?

Answer 2

Skin
Uveal tract of the eye
Leptomeninges of the spinal column

Question 3

What does the MC1R gene do?

Answer 3

Determines balance of pigment by turning phaemelanin into eumelanin.

Question 4

What does 2 defective copies of this gene cause?

Answer 4

Red hair and freckles!

Question 5

What are ephilides?

Answer 5

freckles

Question 6

What causes ephilides?

Answer 6

One defective copy of the MCR1 gene

Question 7

What are liver spots known as?

Answer 7

Actinic lentigines

Question 8

Where are liver spots most common at?

Answer 8

Face, forearms and dorsal hands.

Question 9

What causes melanocytic naevi?

Answer 9

The melanocyte: keratinocyte ratio breaks down so more melanocytes.

Question 10

What is a sporadic dysplastic naevi?

Answer 10

> 6mm diameter with variegated pigment and has no familial link

Question 11

True or False

Familial dysplastic naevi have a strong link with developing melanomas

Answer 11

True

Question 12

True or False

Malignant melanomas are more common in females.

Answer 12

True

Question 13

What type of melanoma affects the trunk and limbs ?

Answer 13

Superficial spreading

Question 14

What type of melanoma affects sun-damaged face/head/scalp?

Answer 14

Lentigo maligna

Question 15

What type of melanoma affects the mucosa?

Answer 15

Acral/mucosal lentiginous

Question 16

What does RGP stand for?

Answer 16

Radial growth phase.

E.g. macules in-situ

Question 17

Why do VGP melanomas metastasise?

Answer 17

Blood and lymphatic access.

RGP melanomas are restricted to the epidermis.

Question 18

How does nodular melanoma differ from other melanomas?

Answer 18

Begin as a nodule as opposed to a macule/patch.

Much more aggressive.

Question 19

What is prognosis related to?

Answer 19

Breslow thickness of tumour

Question 20

what does in-situ mean?

Answer 20

100% survival since cancer cells are present but no melanoma is yet present.

Question 21

How thick is a stage 2 tumour?

Answer 21

1-2mm. v

it has an 80% survival rate.

Question 22

How thick is a stage 4 tumour?

Answer 22

> 4mm thick.

20% survival

Question 23

What does the suffix -b mean in staging?

Answer 23

Presence of ulceration

Question 24

Describe the spread of malignant melanomas

Answer 24

1. dermal lymphatics.
2. regional lymph node metastases
3. blood spread to heart, lungs, GI tract, brain.

Question 25

What are satellite deposits?

Answer 25

First stage of metastasis.

Question 26

What is the primary treatment for melanoma?

Answer 26

Excision and send to pathology.

Question 27

What is a sentinel node biopsy?

Answer 27

Radioactive tracer and blue dye inserted to see which node the lymphatics drain into.
If this node is positive then all nodes are removed.

Question 28

What is a BRAF mutation?

Answer 28

Mutation of an oncogene.

Question 29

What colours of naevi are red flag signs?

Answer 29

Red, white, blue and black

Question 30

True or False

Melanoma can regress.

Answer 30

True.

Metastases can appear after the melanoma has disappeared