Nevi And Bengin Tumors

Question 1

Melanocyte information

Answer 1

Neural crest derived cells

During embryogenesis is found in the epidermis, hair follicles, inner ear and uveal tract of the eye and leptomeninges

In normal skin = found in basal layer

Each melanocytes are associated with 30-40 keratinocytes which transfer melanosomes

melanosome size and melanocyte activity = darker skin. NOT overall number increased

Question 2

3 basic nevi types

Answer 2

1) junctional
- melanocytes are found at the epidermis and dermis junctions
- flat and highly pigmented

2) compound
- raised with mild pigmentation

3) intradermal
- melanocytes are only found in the dermis
- raised with NO pigmentation

Question 3

Congenital nevus

Answer 3

Will be present at birth or during very early infancy

- looks dysplastic however there is 0% risk of melanoma (unless > 20cm in diameter (then 2-3%))

Question 4

Epidermal nevus

Answer 4

Occurs within 1st year of life
- 1:1000 rates

Males and females are equally affected

Occurs along a linear array along blaschko lines
- are hyperpigmented papillomatous

Question 5

Nevus sebaceous

Answer 5

Most common face/scalp and then neck or trunk

Is a thin hairless yellow/orange pebbly plaque that thickens during adolescence years
- lines of blaschko are not very apparent

Can develop into BCC but rates are 1% so pretty low

Question 6

Ephilides

Answer 6

Are also called freckles
- are never present at birth

Are in sun exposed areas and are never seen on mucosal surfaces

Question 7

Lentiginous

Answer 7

Also called “liver spots”

Most common in adults over 60yrs

Are tan to dark black macules in sun exposed areas

• can be seen in mucosal surfaces
• if so screen for PJ-syndrome and colon cancer in the family

can possibly evolve into a type of melanoma called lentigo maligna

Question 8

Cafe au lait Macules /patches

Answer 8

10-20% of population

Usually noted in infancy or early childhood

if multiple = can be neurofibromatosis and need to screen for this

• • if in the armpits or genitalia = crows sign
• need to defiantly screen for neurofibromatosis

Question 9

Dermal melanocytosis

Answer 9

Mongolian spots

Blue-gray patches that are present at birth

Most common location is lumbrosacral areas

Typically resolve on their own

Question 10

Halo Nevus

Answer 10

Younger patients show this often

Has a pallor ring around the pigmented center
- overtime turns into vitiligo like apperance that goes away over time

Is an autoimmune issue but benign

Question 11

Eclipse nevus

Answer 11

Dark ring around a central pallor
(Opposite of halo)

Is benign but if you biopsy it it will comeback as abnormal