skin cancer

Question 1

Basal cell carcinoma is cancer of what cells? what does it resemble?

Answer 1

germinative keratinocytes; resemble basal layer

Question 2

Squamous cell carcinoma is cancer of what cells? what does it resemble?

Answer 2

epidermal keratinocytes; resembles spinous layer

Question 3

Melanoma is cancer of what cells? What leads to the dark color?

Answer 3

melanocytes => more melanomes

Question 4

How does the most common invasive neoplasm in US arise?

Answer 4

BCC arises from PTCH mutations (1/3) which is the basal epidermal cell proliferation regulator

Question 5

What are the risks for BCC?

Answer 5

UV; blistering sunburns; Family Hx; immunosuppression (drugs, disease, transplant)

Question 6

How do BCC present histologically?

Answer 6

basophilic hyperchromatic cells form nodules extending from epidermal surface; cells at periphery form a palisade; nodules are in a mucinous stroma w/ some retraction

Question 7

How does classic BCC present grossly?

Answer 7

well circumscribed nodule with pearly rolled border and central erosion with telangiectasias

Question 8

Why would a germline mutation in PTCH be considered of BCC before 35?

Answer 8

only 20% of BCC presents before age 50 and rare prior to age 35

Question 9

What is associated with Basal cell nevus syndrome?

Answer 9

AD mutation of PTCH1 that presents BCCs around 23 y/o with defects and jaw cysts; increased risk of other neoplasms

Question 10

How likely is BCC to metastasize? Tx?

Answer 10

very very rare; Tx is excision and topical Tx for superficial BCC

Question 11

What is targeted therapy for advanced BCC and its MOA?

Answer 11

Vismodegib; small molecule inhibitor of SMO

Question 12

How does a squamous cell carcinoma typically grossly present?

Answer 12

nodule with crusts

Question 13

What is the likely progression of squamous cell carcinoma?

Answer 13

1) Actinic keratosis; 2) SCC in situ (full thickness epi atypia above basement membrane); 3) SCC invasive based on levels of differentiation

Question 14

How does actinic keratosis present?

Answer 14

thin plaques that are superficial in nature

Question 15

Histologically, how does SCC present?

Answer 15

invasion through basal layers with keratinizing pink cells (keratin pearls)

Question 16

What leaves a person with an increased risk for developing SCC?

Answer 16

UV; HPV; immunosuppression; chronic inflammation

Question 17

In cutaneous SCC, what is the risk of metastasis related to?

Answer 17

size of tumor (>2cm), depth of invasion into dermis(>4mm), anatomic site (lips/ears), host immune status

Question 18

Though rare, where does SCC metastasize?

Answer 18

lymph nodes and lung

Question 19

What cancer would be likely to be present on a plaque of leukoplakia and secondary to tobacco use?

Answer 19

SCC

Question 20

What is a keratoacanthoma?

Answer 20

neoplasm of keratinocytes that rapidly grows over weeks then spontaneously goes away

Question 21

What is Marjolin’s ulcer?

Answer 21

ulcerated invasive SCC w/ background of chronic inflammation, scarring, radiation, trauma

Question 22

How is SCC treated?

Answer 22

depends on progression: Actinic keratosis (topical, cryo); SCC in situ (topical, intralesional, excision); invasive SCC (excision)

Question 23

Who is at the highest risk for melanoma?

Answer 23

caucasian men > 50yo

Question 24

T/F Melanoma is commonly associated with mole

Answer 24

FALSE, 80% are de novo and not assoc with a mole

Question 25

When can melanoma metastasize?

Answer 25

if it is in the dermis

Question 26

What are the 3 different types of nevi?

Answer 26

junctional, compound, intradermal

Question 27

What is a distinguishing feature of the melanocytes in nevi and melanoma?

Answer 27

maturity with descent into dermis of nevi (none above basal layer)
vs
immaturity of melanocytes on descent (located above basal layer)

Question 28

What type of growth phase is melanoma in situ?

Answer 28

radial growth due to attachment via dendrites so cannot metastasize

Question 29

What is the relationship of nevi and melanoma?

Answer 29

Both comprised of melanocytes, share some mutations (BRAF) => high nevi increase risk of melanoma

Question 30

Describe melanoma’s multifactorial etiology

Answer 30

genetic predispostion; environment; underlying immune status

Question 31

How is screening done for melanoma?

Answer 31

Asymmetry;
Borders: irregular, scalloped
Color: mottled, non uniform
Diameter: >6mm
Elevation

Question 32

What type of melanoma will occur in people of dark sin? Where is it located typically?

Answer 32

acral lentiginous melanoma => palms/soles/subungual skin

Question 33

What type of metastatic potential does lentigo maligna have?

Answer 33

slow growing and still in radial growth phase (melanoma in situ)

Question 34

How does a superficial spreading melanoma present grossly?

Answer 34

Red white and blue

Question 35

What is the most common site of melanoma histologically?

Answer 35

dermal-epidermal junction

Question 36

What is the most common organ site for metastatic melanoma?

Answer 36

skin

Question 37

What is the most common cause of death in melanoma?

Answer 37

CNS involvement

Question 38

What is the single most important prognostic factor in melanoma?

Answer 38

lymph node involvement

Question 39

What is the most important histological prognostic factor?

Answer 39

Breslow thickness and ulceration

Question 40

What is breslow’s thickness?

Answer 40

distance of involvement from stratum granulosum to deepest tumor cell

Question 41

What is the most common treatment for metastatic melanoma?

Answer 41

IFNa; combo CTX; XRT; vaccine Tx

Question 42

How does the 1st targeted Tx for melanoma work?

Answer 42

Vemurafenib inhibits BRAF in stage 4 melanoma that improves survival benefit but cells adapt

Question 43

What is the pathogenesis of XP?

Answer 43

defects in genes that function in nucleotide excision repair of thymine dimers leading to increase skin cancer from insensitivity to UV light