CH 25: SKIN

Question 1

What benign lesions can pop up during pregnancy, implying hormonal involvement in their pathogenesis?

Answer 1

Malanocytic nevi
Fibroepithelial polyp (skin tags)

Question 2

Are lentigos sunlight-responsive?

Answer 2

No

Question 3

Are freckles sun-light responsive?

Answer 3

Yes

Question 4

What biochemical pathway is intact in Melanocytic Nevi (moles)?

Answer 4

CDKN2A (makes p16/INK4a)

Question 5

What is melanoma correlated with?

Answer 5

Exposure to UV radiation in sunlight, which causes one to acquire mutations

Question 6

What’s mutated in melanomas not associated w/ sun-exposed areas?

Answer 6

KIT (R tyrosine kinase)

Question 7

What are the ABCDE warning signs of melanoma?

Answer 7

A = asymmetry
B = borders (irregular)
C = color (varieties)
D = diameter (increses)
E = evolution (rapid change)

Question 8

What differentiates Suborrheic Keratoses from melanomas?

Answer 8

Pore-like ostia impacted w/ keratin

Question 9

What’s Lese-Trelat sign?

Answer 9

Sudden appearance of many seborrheic keratoses (“coin-like” lesions) d/t stimulation of keratinocytes by TGF-a produced by tumor cells (carcinomas of the GI)

Question 10

What are keratinocytes?

Answer 10

Squamous epithelial cells

Question 11

Common etiology for acanthosis nigricans (80%)? Remaining?

Answer 11

Childhood/puberty: obesity, diabetes, endocrine tumors (pituitary or pineal)

Middle-aged/older: associated w/ cancers of the GI (adenocarcinomas, a paraneoplastic phenomenon)

Question 12

What are dermatosis papulosa nigra?

Answer 12

Seborrheic Keratoses in people of color

Question 13

What are the different types of melanocytic nevi?

Answer 13

Junctional
Compound
Dermal
Dermal w/ neurotization

Question 14

What are familial trichoepithelioma and Brooke-Spiegler syndrome associated w/?

Answer 14

Germline mutations in CYLD causing multiple adenexal tumors

Familial trichoepithelioma = follicular tumor
B-S syndrome = cylindroma

Question 15

What is the cylindroma mutation? What’s it do?

Answer 15

CYLD

Encodes an enzyme that regulates NF-kB

Question 16

What does eccrine refer to?

Answer 16

Sweat glands on the skin

Question 17

What does actinic mean? What’s this associated w/? What’s the prominent feature?

Answer 17

Light being able to cause photochemical reactions

SCC precursor lesion Actinic Keratosis

Cutaneous horn of keratin

Question 18

What’s the most common to least common list of prominent skin CAs?

Answer 18

Basal-cell carcinoma > SCC > melanoma (common, most deadly skin CA)

Question 19

Melanoma and SCC are associated w/ sun exposure how?

Answer 19

Melanoma = childhood UV exposure

SCC = lifetime sun exposure

Question 20

What HPV viruses are associated w/ immunodeficient-caused SCC?

Answer 20

5 and 8

Question 21

What mutations are associated w/ SCC?

Answer 21

TP53

Inc RAS signaling

Dec Notch signaling

Question 22

What is xeroderma pigmentosum and what’s it associated w/?

Answer 22

Autosomal recessive dx in which the pt has extreme sensitivity of UV light and must avoid the sun, “moon child”, causes dry skin

SCC and BCC

Question 23

Does SCC come as an in situ lesion?

Answer 23

Yes, where it doesn’t break past the dermoepidermal junction

Question 24

What mutation is associated w/ BCC?

Answer 24

Mutations that activate the Hedgehog pathway

• LOF for PTCH
• activating mutations in SMO

Question 25

What is the most common invasive CA in humans?

Answer 25

Basal Cell Carcinoma of the skin

Question 26

How do BCCs present morphologically?

Answer 26

Pearly papules w/ telangiectasias

Question 27

What happens if you neglect a BCC?

Answer 27

On rare occasions, can extensively invade locally to bone or facial sinuses

Question 28

Basal (sounds like basement) cell carcinomas are associated w/ what archaic designation?

Answer 28

Rodent ulcers, referring to the local invasion of the CAs over time if neglected

Question 29

Are metastasis common in BCC?

Answer 29

No

Question 30

Young-middle aged woman finds a skin lesion on her leg, what is it?

Answer 30

Benign Fibrous Histiocytoma (Dermatofibroma is the most common form)

Question 31

What are Benign Fibrous Histiocytomas (Dermatofibromas) at least partially composed of?

Answer 31

Factor XIIIa-positive dermal dendritic cells

Question 32

What's the mutation associated w/ Dermatofibrosarcoma Protuberans?

Answer 32

Translocation involving: COL1A1 and PDGFB - COL1A1: encodes collagen 1A1 - PDGFB: encodes platelet-derived growth factor-B

Question 33

What's CTCL?

Answer 33

Cutaneous T-Cell Lymphoma The specific one we're referring to is Mycosis Ungoides

Question 34

What's Sezary syndrome?

Answer 34

Seeding of the blood by malignant T cells accompanied by diffuse erythema and scaling of the entire body surface (erythroderma) Occurs in Mycosis Fungoides, a CTCL

Question 35

What morph eatures are associated w/ Mycosis Fungoides?

Answer 35

Sezary-Lutzner cells (which form bandlike aggregates within superficial dermis - can invade epidermis as single cells or groups (Pautrier microabscesses)

Question 36

What is the Mastocytosis we're studying and what population does it affect?

Answer 36

Urticaria pigmentosa Children

Question 37

What's the Darier sign and what's it associated w/?

Answer 37

Localized are of dermal edema and erythema (wheal) occurring when lesional skin is rubbed - urticaria pigmentosa, a Mastocytosis

Question 38

What's ichthy Greek for?

Answer 38

Fishy