skin cancer Flashcards
Basal cell carcinoma is cancer of what cells? what does it resemble?
germinative keratinocytes; resemble basal layer
Squamous cell carcinoma is cancer of what cells? what does it resemble?
epidermal keratinocytes; resembles spinous layer
Melanoma is cancer of what cells? What leads to the dark color?
melanocytes => more melanomes
How does the most common invasive neoplasm in US arise?
BCC arises from PTCH mutations (1/3) which is the basal epidermal cell proliferation regulator
What are the risks for BCC?
UV; blistering sunburns; Family Hx; immunosuppression (drugs, disease, transplant)
How do BCC present histologically?
basophilic hyperchromatic cells form nodules extending from epidermal surface; cells at periphery form a palisade; nodules are in a mucinous stroma w/ some retraction
How does classic BCC present grossly?
well circumscribed nodule with pearly rolled border and central erosion with telangiectasias
Why would a germline mutation in PTCH be considered of BCC before 35?
only 20% of BCC presents before age 50 and rare prior to age 35
What is associated with Basal cell nevus syndrome?
AD mutation of PTCH1 that presents BCCs around 23 y/o with defects and jaw cysts; increased risk of other neoplasms
How likely is BCC to metastasize? Tx?
very very rare; Tx is excision and topical Tx for superficial BCC
What is targeted therapy for advanced BCC and its MOA?
Vismodegib; small molecule inhibitor of SMO
How does a squamous cell carcinoma typically grossly present?
nodule with crusts
What is the likely progression of squamous cell carcinoma?
1) Actinic keratosis; 2) SCC in situ (full thickness epi atypia above basement membrane); 3) SCC invasive based on levels of differentiation
How does actinic keratosis present?
thin plaques that are superficial in nature
Histologically, how does SCC present?
invasion through basal layers with keratinizing pink cells (keratin pearls)
What leaves a person with an increased risk for developing SCC?
UV; HPV; immunosuppression; chronic inflammation
In cutaneous SCC, what is the risk of metastasis related to?
size of tumor (>2cm), depth of invasion into dermis(>4mm), anatomic site (lips/ears), host immune status
Though rare, where does SCC metastasize?
lymph nodes and lung
What cancer would be likely to be present on a plaque of leukoplakia and secondary to tobacco use?
SCC
What is a keratoacanthoma?
neoplasm of keratinocytes that rapidly grows over weeks then spontaneously goes away
What is Marjolin’s ulcer?
ulcerated invasive SCC w/ background of chronic inflammation, scarring, radiation, trauma
How is SCC treated?
depends on progression: Actinic keratosis (topical, cryo); SCC in situ (topical, intralesional, excision); invasive SCC (excision)
Who is at the highest risk for melanoma?
caucasian men > 50yo
T/F Melanoma is commonly associated with mole
FALSE, 80% are de novo and not assoc with a mole
When can melanoma metastasize?
if it is in the dermis
What are the 3 different types of nevi?
junctional, compound, intradermal
What is a distinguishing feature of the melanocytes in nevi and melanoma?
maturity with descent into dermis of nevi (none above basal layer)
vs
immaturity of melanocytes on descent (located above basal layer)
What type of growth phase is melanoma in situ?
radial growth due to attachment via dendrites so cannot metastasize
What is the relationship of nevi and melanoma?
Both comprised of melanocytes, share some mutations (BRAF) => high nevi increase risk of melanoma
Describe melanoma’s multifactorial etiology
genetic predispostion; environment; underlying immune status
How is screening done for melanoma?
Asymmetry; Borders: irregular, scalloped Color: mottled, non uniform Diameter: >6mm Elevation
What type of melanoma will occur in people of dark sin? Where is it located typically?
acral lentiginous melanoma => palms/soles/subungual skin
What type of metastatic potential does lentigo maligna have?
slow growing and still in radial growth phase (melanoma in situ)
How does a superficial spreading melanoma present grossly?
Red white and blue
What is the most common site of melanoma histologically?
dermal-epidermal junction
What is the most common organ site for metastatic melanoma?
skin
What is the most common cause of death in melanoma?
CNS involvement
What is the single most important prognostic factor in melanoma?
lymph node involvement
What is the most important histological prognostic factor?
Breslow thickness and ulceration
What is breslow’s thickness?
distance of involvement from stratum granulosum to deepest tumor cell
What is the most common treatment for metastatic melanoma?
IFNa; combo CTX; XRT; vaccine Tx
How does the 1st targeted Tx for melanoma work?
Vemurafenib inhibits BRAF in stage 4 melanoma that improves survival benefit but cells adapt
What is the pathogenesis of XP?
defects in genes that function in nucleotide excision repair of thymine dimers leading to increase skin cancer from insensitivity to UV light
