19.4: Disorders of pigmentation and Melanocytes

Question 1

What are the organelles in which melanin is produced in melanocytes?

Answer 1

melanosomes

Question 2

True or false: keratinocyte produce the melanin found within them

Answer 2

False- melanocytes produce the pigment, then ship it off to local keratinocytes

Question 3

Which layer of the epidermis are melanocytes found in?

Answer 3

Basal layer

Question 4

Melanocytes are derived from what type of cells in development?

Answer 4

Neural crest cells

Question 5

What is the precursor amino acid that is needed to produce melanin? What is the enzyme that converts it?

Answer 5

• Tyrosine

- Tyrosinase

Question 6

What, generally, is vitiligo?

Answer 6

Autoimmune destruction of the melanocytes, resulting in a localized loss of skin pigmentation

Question 7

How does Vitiligo present?

Answer 7

Localized areas of a lack of skin pigmentation

Question 8

What is the enzyme that is usually deficient in albinism?

Answer 8

Tyrosinase

Question 9

What is the concern with albinism, besides cosmetic / psychological effects?

Answer 9

Increased risk of skin cancer

Question 10

What causes a freckle to darken with sunlight?

Answer 10

Increased numbers of melanosomes (NOT melanocytes)

Question 11

What is melasma?

Answer 11

Mask-like hyperpigmentation of the cheeks, associated with pregnancy and oral contraceptives

Question 12

What is a nevus?

Answer 12

Benign neoplasm of melanocytes (“mole”)

Question 13

Do congenital or acquired nevi usually have hair associated with them?

Answer 13

Congenital

Question 14

Will there be hair in melanoma?

Answer 14

No–only melanocytes

Question 15

What are junctional nevi, and what age group are they usually found in?

Answer 15

melanocytes that progress through the epidermis, all the way to the dermal-epidermal junction

Question 16

What is a compound nevus?

Answer 16

Nevus with melanocytes extending into the dermis

Question 17

What is an intradermal nevus? In what age range is this common in?

Answer 17

Nevus that is fully comprised of dermal cells, without a junctional component

Question 18

What is melanoma?

Answer 18

Malignant proliferation of melanocytes

Question 19

What skin cancer is the most lethal?

Answer 19

Melanoma

Question 20

What is dysplastic nevus syndrome? What is the inheritance pattern?

Answer 20

AD disorder, characterized by formation of dysplastic nevi that may progress to melanoma

Question 21

What are the ABCDEs of melanoma?

Answer 21

• Asymmetry
• Borders (irregular)
• Color (not uniform)
• Diameter more than 6 mm
• Evolution

Question 22

A diameter greater than how many mm for a nevus is concerning for melanoma?

Answer 22

6mm

Question 23

What are the two growth phases of melanoma?

Answer 23

• Radial growth along dermal/epidermal junction

- Vertical growth

Question 24

What is the key risk factor for the development of metastases with melanocytes?

Answer 24

Vertical depth

Question 25

What is lentigo malignant melanoma? Prognosis?

Answer 25

"lentiginous proliferation of melanocytes--meaning along the dermal - epidermal border -Good prognosis

Question 26

What is the superficial spreading subtype of melanoma? Prognosis?

Answer 26

- Melanoma with dominant early radial phase | - Good prognosis

Question 27

What is the nodular form of melanoma? Prognosis?

Answer 27

- Melanoma with a vertical growth phase that begins early | - Poorer prognosis

Question 28

What is acral lentiginous melanoma? Where on the body does it arise?

Answer 28

-Melanoma that arises on the palms or soles, often in dark skinned individuals

Question 29

Which subtype of melanoma is not related to UV light exposure?

Answer 29

Acral lentiginous

Question 30

What ethnicity is acral lentiginous melanoma more common in?

Answer 30

Dark-skinned individuals