Disorders of Pigmentation and Melanocytes Flashcards Preview

Pathoma - Skin Pathology Ch19 > Disorders of Pigmentation and Melanocytes > Flashcards

Flashcards in Disorders of Pigmentation and Melanocytes Deck (21)
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1
Q

What are melanocytes responsible for and where are they present in the skin?

A

Skin pigmentation; Basal layer of epidermis

2
Q

What are melanocytes derived from?

A

Neural crest cells

3
Q

How do melanocytes function?

A

They synthesize melanin in melanosomes using tyrosine as a precursor molecule and pass melanosomes to keratinocytes

4
Q

What is vitiligo?

A

Localized loss of skin pigmentation do to autoimmune destruction of melanocytes

5
Q

What is albinism?

A

Congenital lack of pigmentation due to enzyme defect that impairs melanin production

6
Q

What are the two types of albinism?

A

Ocular and oculocutaneous

7
Q

What conditions do albinism increase your risk for?

A

SCC, BCC and melanoma due to UVB

8
Q

What is another name for a freckle? What is a freckle? What gives freckle its characteristic appearance?

A

Ephelia; Small tan brown macule that darkens when exposed to light due to increased melanosomes (melanocytes are NOT increased)

9
Q

What is a melasma? What is melasma associated with?

A

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

10
Q

What is a nevus?

A

Benign neoplasm of melanocytes associated with hair characterized as a flat macule or raised papule with symmetry, sharp borders, evenly distributed color and small diameter (<6 mm); Nevus can be congenital or acquired

11
Q

Describe to process of acquired nevus formation

A

Begin as nest of melanocytes at the dermal-epidermal junction which grows by extension into the dermis. Junctional component eventually lost resulting in an intradermal nevus, which is the most common mole in adults

12
Q

What can a dysplastic nevus lead to?

A

Melanoma

13
Q

What is melanoma?

A

Malignant neoplasm of melanocytes; MOST common cause of death from skin cancer

14
Q

What are risk factors for melanoma?

A

UVB-induced DNA damage, prolonged exposure to sunlight, albinism, xeroderma pigmentosum, dysplastic nevus syndrome (Autosomal dominant disorder characterized by formation of dysplastic nevi)

15
Q

What are the ABCDs of melanoma?

A

Asymmetry, Borders irregular, Color not uniform, Diameter >6 mm

16
Q

What are the two growth phases of melanoma?

A

1) Radial growth along dermis and superficial epidermis (low risk for metastasis) 2) Vertical growth into the deep dermis resulting in increased risk of metastasis

17
Q

What is the most important prognostic factor in predicting melanoma prognosis?

A

Breslow thickness (depth of extension)

18
Q

What is the most common subtype of melanoma?

A

Superficial spreading resulting in dominant early radial growth (good prognosis)

19
Q

What is lentigo maligna melanoma?

A

Lentiginous proliferation along epidermal-dermal junction (good prognosis)

20
Q

What is nodular melanoma?

A

Early vertical growth (poor prognosis)

21
Q

What is Acral Lentiginous melanoma?

A

Melanoma arising on pals or soles often in dark-skinned individuals; Not related to UV exposure