deck Flashcards
List the major cell types in the epi:
keratocytes:
- basal cell layer
- prickle cell or squamous
- granular (keratin)
- stratified squamous (lack nuclei)
clear cells:
-melanocytes
- merkel cells
- Langerhans cells
what is this? what are some associated characteristics? characteristic histo finding? what cell layer is being affected

seborrheic keratosis: raspberry waxy stuck on
pseudo horn cysts: accum of keratin (must be diff from pearls of squam cell carc.)
- proliferation of basal cells with various amounts of acanthosis (proliferation of squamous cells) -> usually broad-based and sessile
- greasy-looking lesions, “brown wax dripped on a background”
- varying amount of pigmentation

T/F: seborrheic keratosis is actinic
false
what causes seborrheic keratosis?
Idiopathic
what is Leser-Trelat sign:
- Leser-Trelat sign: fairly young and suddenly many seb keratosis lesions are appearing is more worrisome – linked to visceral cancers
tx for seborrheic keratosis?
- if small: observe, excision/curettage, cryosurgery involving “treat and retreat” with liquid nitrogen, electrodissection
- if 5mm+: debulk/shave, treat base with cryosurgery
what is this?
what are some associated characteristics?
characteristic histo finding?
what cell layer is being affected?
describe the typical time course of a keratoacathoma

keratoacanthoma;
- nodular: cup-shape, keratin core, pedunculated, rolled borders
- rapid growth – peak size within 6-8 weeks
- spontaneous involution/resolution may occur
- inflammation: micro-abscesses and inflammatory cells within and at base of lesion -> cells at base probably preventing from invading into lower tissue (mixed leukocytes w/ some dermal invasion)
- *very little cell atypia but mitotic figures can be seen

what is pseudoepitheliomatous hyperplasia of eyelids? what other eyelid growth might it resemble? what will histo reveal?
- a type of keratocanthoma, but mimics basal cell carcinoma bc edges are raised and center is umbilicated / necrotic
- BIOPSY!
- path/histology: mixed leukocytes, some dermal invasion
- little cell atypia, but some mitotic features because rapidly growing
what causes keratoacanthoma?
probably UV light, possibly carcinogen exposure, HPV (some biopsies but this may be comorbidity rather than truly causal)
ALSO: usually originates from hair follicle
tx for keratoacanthoma? also include alt therapies.
are steroids effective?
- small: observation (usually go away by themselves), cryosurgery (if taking too long to resolve)
- 5mm or more: excisional biopsy (if persisting for more than 8 weeks) – needs to be deep to reveal normal tissue underneath
- alternative therapies:
- 5-FU, an anti-metabolite
- mitomycin C (alkylating agent),
- intralesional steroid bc of inflammatory component, but not very effective
- oral eretinate (can be used if many lesions, i.e. in cases of HIV/AIDS)
- oral methotrexate (antimetabolite blocks folic acid synthesis)
HPV is what kind of virus? where does it live in epidermis? what does it do/inactivate?
- live in basal epithelium, not activated until infected cell begins migration upward
- inactivates the p53 protein -> disables apoptosis, causes massive proliferation of the cells
- tons of viral replication in the highly differentiated keratinocytes
- may become cancerous via other mutations
what changes in epi layer occur in benign squamous papilloma (AKA skin tag)?
how is it different from verruca?
variable keratosis over fibrovascular core (key point)
- viral often have looping vascular pattern in fibrous tissue
- verruca will have viral inclusions and koilocytes on histology
pathogen. of papilloma? verruca?
- verruca: HPV, wart, p53 activation
- benign squamous papilloma: genetic damage because of environmental factors
tx for papilloma or verruca:
list some alt tx therapies as well
- small: observe, cryosurgery, keratolytic agents (acids), electrodessication, excision and curettage
- 5mm+: debulk, treat base with cryo
alternate topical therapies:
- cantharidin
- podophyllin (astringent from may-apple tree),
- retin A cream
- cidofovir (developed in HIV era for CMV, works as a DNA chain terminator to interrupt all cell division)
- alternate oral therapies: isoretinoin with caution
patho of molluscum:
how to tx? list some alt tx forms, too
- DNA pox virus
- self-limiting but highly contagious
- *varying degrees of inflamm, crops or singular
TX:
- small: observe, cryosurgery, cantharidin, podophyllin, bichloroacetic acid
- alternate therapies: Australian lemon myrtle oil, tea tree oil, duct tape (works in some people)
- SilverCure device, Zymadem (OTC-naturopathic found in tea tree and other natural oils)
telangiectasia vs angioma
- Telangiectasia – dilated but normal blood vessels that have become damaged and cannot recover
- Angioma – new vessel growth
what is this precursor to squam cell carc? what are some key histo findings?

- act. keratosis (but resembles SCC)
- histo: inflamm, various keratosis + pigment; exagg. surface topo
- typically full thickness dysplasia (cells irregular, loss of polarity)
- squamous eddies: epi cells swirling around the keratin due tohigh turnover
- usually intact BM w/inflammatory cells below
list one of the possible benign DDx of actinic keratosis:
- DDx: roasacea, but this would have thickened, ruddy skin with papules and pustules
what % of act keratosis proceed to squam cell carc
5%
patho of act keratosis
- Pathogenesis: UV exposure -> mild atypia, dysplasia, polarity loss, elastosis, base inflammation
tx for act keratosis (small vs large)
- if small: cryotherapy
- if broad based:
- 5-FU cream-causes epithelium to slough off
- PDT 5-ALA
- Solarize – an NSAID with unclear mechanism in this case (COX-2 inhibits PGE2)
- Imiquimod cream – suppresses the upregulation of growth via some opioid receptors
- Ingenol gel (plant extract) – 3d course with amazing results, but an unknown mechanism
what is Bowen’s disease? *
carcinoma in-situ -> not a UV-light induced lesion, can occur in non-sun-exposed areas
what is Xeroderma pigmentosum? predisposed to what condition?
-
AR trait, most common in the Japanese
- defective enzymes can’t replace DNA damage in cell
predisposed to squam cell carc
what are some classic features of squamous cell carc? histo feat?
squam cell carc, NO classic features, gotcha bitch
-
keratin pearls on histology
- suggest squam vs BCC



























