Skin Cancer B&B Flashcards
what are the 3 types of skin cancers and the cell types which drive them?
- basal cell (most common) = stem cells (stratum basal)
- squamous cell = keratinocytes
- melanoma = melanocytes (epidermis-dermis junction)
actinic keratosis
aka solar keratosis: premalignant skin lesions caused by sun exposure
growth of atypical epidermal keratinocytes - round, red/brown papules or plaques
can lead to squamous cell carcinoma
premalignant skin lesions caused by sun exposure
actinic keratosis, aka solar keratosis: growth of atypical epidermal keratinocytes - can lead to squamous cell carcinoma
round, red/brown papules or plaques in sun exposed areas
what does biopsy of actinic keratosis show?
premalignant skin lesions caused by sun exposure, growth of atypical epidermal keratinocytes - can lead to squamous cell carcinoma
round, red/brown papules or plaques in sun exposed areas
biopsy: perakaratosis (retained nuclei in stratum corneum), hyperkeratosis, epidermal cell dysplasia
how do squamous cell carcinoma lesions appear, and what is the hallmark pathological finding?
red, scaling plaques with sharp borders; advanced lesions may ulcerate/crust/bleed
pathology shows keratin pearls (look like roses or onions)
in which patients is squamous cell carcinoma most common? what are the risk factors (4)?
2nd most common skin cancer, occurs in older patients (>75)
risk factors: sun exposure, chronic immunosuppression, chronic skin inflammation, arsenic exposure
note <5% metastasize
Pt is A 76yo M presenting with red, scaling plaque with well-demarcated borders on their ear. PMH includes a kidney transplant 10 years ago. what do you suspect the biopsy will show? What is the prognosis?
most likely squamous cell carcinoma - pathology shows keratin pearls (look like roses or onions)
2nd most common skin cancer, occurs in older patients (>75)
risk factors: sun exposure, chronic immunosuppression, chronic skin inflammation, arsenic exposure
note <5% metastasize
arsenic exposure is a risk factor for which type of skin cancer?
squamous cell carcinoma
arsenic may be found in contaminated drinking water
how do keratoacanthomas appear? describe the disease progression - how are they treated?
variant of squamous cell carcinoma, usually benign and self-limited
dome-shaped nodule with central hyperkeratosis (black spot)
grow rapidly (weeks), but then regress - removed surgically or followed for regression
Pt presents to dermatologist with a dome-shaped nodule with central hyperkeratosis, which they state has grown rapidly in size over the past 2 weeks. Diagnosis? How will you treat it?
keratoacanthoma: variant of squamous cell carcinoma, usually benign and self-limited
grow rapidly (weeks), but then regress - removed surgically or followed for regression
how does Bowen’s Disease appear?
squamous cell carcinoma in situ - hasn’t broken through basement membrane and invaded dermis
well-demarcated, scaly patch or plaque
what is the most common form of skin cancer, and how does it progress?
basal call carcinoma: slow growing, rarely metastasize
lowest potential for recurrence or metastases of skin cancers (basal < squamous < melanoma)
most found early and excised
which type of skin cancer is LEAST likely to recur or metastasize?
basal cell carcinoma: also most common
has lowest potential for recurrence/metastases (basal < squamous < melanoma)
how do basal cell carcinoma lesions appear?
pearly/shiny papules or nodules, may have telangiectasia on surface (dilated blood vessels)
may ulcerate with crust in center, borders may be “rolled” (rounded, thickened)
most common type of skin cancer, least likely to metastasize or recur
what will histology of a basal cell carcinoma lesion show? (2)
nests of dark “basaloid” cells in the dermis + palisading nuclei (cells at periphery of nests line up in parallel)
(big round patches like chocolate chips in a cookie)
Pt presents to dermatologist with concern of a skin lesion on their nose. The lesion appears pearly and there are telangiectasia on the surface. A biopsy is taken which shows nests of dark cells with palisading nuclei at the peripheries. What is the most likely diagnosis, and what is the prognosis?
basal call carcinoma: slow growing, rarely metastasize
lowest potential for recurrence or metastases of skin cancers (basal < squamous < melanoma)
how does superficial basal cell carcinoma appear? (variant of BCC) where does it most likely occur?
light red to pink plaques with slight scaling
most commonly occur on the trunk
can be easily mistaken for psoriasis or other skin disorders
how can melanoma be recognized?
ABCDE:
Asymmetrical
Borders are irregular
Color variation
Diameter >6mm
Evolving over time
[most malignant form of skin cancer, and highly malignant at that!]
what are the 2 main subtypes of melanoma?
- superficial spreading: most common, spreads laterally on the surface (initially)
- nodular: aggressive subtype, grows vertically to form nodules (into dermis)
lentigo maligna
lentigo = small, dark, flat spot (large freckle), confined to epidermis
lentigo maligna = growing dark spot confined to epidermis (“melanoma in situ”)
lentigo maligna melanoma = invasion of dermis, but slow growing - take years to develop (occur in elderly)
which patients most commonly present with acral lentiginous? where does it occur?
least common type of melanoma (<5%) EXCEPT it is most common type in dark-skinned patients (African, Asian)
occurs on extremities - palms, bottom of foot, under nails
most common type of melanoma in dark-skinned patients occurring on palms, bottoms of feet, under nails
acral lentiginous - note, least common type of melanoma overall (<5%)
what is the tumor marker of melanoma?
S100: calcium binding protein in nucleus
highly specific (however low sensitivity - many melanomas lack this marker)
biopsy of lesion is positive for S100 - based on that alone, what is it most likely?
melanoma
S100: calcium binding protein in nucleus
highly specific (however low sensitivity - many melanomas lack this marker)
what is the clinical use of the Breslow thickness?
Breslow thickness = distance from granular epidermis to deepest tumor cells
used to measure depth of melanoma tumor to estimate risk of metastasis
melanoma initially spreads laterally along epidermis, then shifts to vertical growth phase downward in dermis
how does melanoma metastasize (2)? where does it most often metastasize (3)?
metastasis via hematogenous and/or lymphatic spread
spreads to lungs, liver, brain - most common cause of death is metastasis
what is the most common genetic mutation in sporadic melanomas? include the most common specific mutation
BRAF gene mutations (40-50% of sporadic melanomas) due to V600E mutation (90%)
BRAF = proto-oncogene, triggers cell proliferation via RAS pathway
tx is BRAF inhibitors: vemurafenib or dabrafenib
which 2 BRAF inhibitors can be used to treat sporadic melanomas with a BRAF gene mutation?
- vemurafenib
- dabrafenib
BRAF gene mutations (40-50% of sporadic melanomas) due to V600E mutation (90%)
BRAF = proto-oncogene, triggers cell proliferation via RAS pathway
what is the effect of the BRAF proto-oncogene? what pathway is it part of?
growth factor —> tyrosine kinase receptor —> RAS
RAS can activate 1. PI-3K (cell survival) or 2. BRAF (cell proliferation)
fill in the blanks regarding the RAS pathway:
1. growth factor binds ______ receptor
2. receptor activates RAS
3. RAS can activate _____ or ______, respectively leading to ____ or _____
growth factor —> tyrosine kinase receptor —> RAS
RAS can activate 1. PI-3K (cell survival) or 2. BRAF (cell proliferation)
