CH 25: SKIN Flashcards
What benign lesions can pop up during pregnancy, implying hormonal involvement in their pathogenesis?
Malanocytic nevi Fibroepithelial polyp (skin tags)
Are lentigos sunlight-responsive?
No
Are freckles sun-light responsive?
Yes
What biochemical pathway is intact in Melanocytic Nevi (moles)?
CDKN2A (makes p16/INK4a)
What is melanoma correlated with?
Exposure to UV radiation in sunlight, which causes one to acquire mutations
What’s mutated in melanomas not associated w/ sun-exposed areas?
KIT (R tyrosine kinase)
What are the ABCDE warning signs of melanoma?
A = asymmetry B = borders (irregular) C = color (varieties) D = diameter (increses) E = evolution (rapid change)
What differentiates Suborrheic Keratoses from melanomas?
Pore-like ostia impacted w/ keratin
What’s Lese-Trelat sign?
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)
What are keratinocytes?
Squamous epithelial cells
Common etiology for acanthosis nigricans (80%)? Remaining?
Childhood/puberty: obesity, diabetes, endocrine tumors (pituitary or pineal)
Middle-aged/older: associated w/ cancers of the GI (adenocarcinomas, a paraneoplastic phenomenon)
What are dermatosis papulosa nigra?
Seborrheic Keratoses in people of color
What are the different types of melanocytic nevi?
Junctional
Compound
Dermal
Dermal w/ neurotization
What are familial trichoepithelioma and Brooke-Spiegler syndrome associated w/?
Germline mutations in CYLD causing multiple adenexal tumors
Familial trichoepithelioma = follicular tumor
B-S syndrome = cylindroma
What is the cylindroma mutation? What’s it do?
CYLD
Encodes an enzyme that regulates NF-kB
What does eccrine refer to?
Sweat glands on the skin
What does actinic mean? What’s this associated w/? What’s the prominent feature?
Light being able to cause photochemical reactions
SCC precursor lesion Actinic Keratosis
Cutaneous horn of keratin
What’s the most common to least common list of prominent skin CAs?
Basal-cell carcinoma > SCC > melanoma (common, most deadly skin CA)
Melanoma and SCC are associated w/ sun exposure how?
Melanoma = childhood UV exposure
SCC = lifetime sun exposure
What HPV viruses are associated w/ immunodeficient-caused SCC?
5 and 8
What mutations are associated w/ SCC?
TP53
Inc RAS signaling
Dec Notch signaling
What is xeroderma pigmentosum and what’s it associated w/?
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
Does SCC come as an in situ lesion?
Yes, where it doesn’t break past the dermoepidermal junction
What mutation is associated w/ BCC?
Mutations that activate the Hedgehog pathway
- LOF for PTCH
- activating mutations in SMO
What is the most common invasive CA in humans?
Basal Cell Carcinoma of the skin
How do BCCs present morphologically?
Pearly papules w/ telangiectasias
What happens if you neglect a BCC?
On rare occasions, can extensively invade locally to bone or facial sinuses
Basal (sounds like basement) cell carcinomas are associated w/ what archaic designation?
Rodent ulcers, referring to the local invasion of the CAs over time if neglected
Are metastasis common in BCC?
No
Young-middle aged woman finds a skin lesion on her leg, what is it?
Benign Fibrous Histiocytoma (Dermatofibroma is the most common form)
What are Benign Fibrous Histiocytomas (Dermatofibromas) at least partially composed of?
Factor XIIIa-positive dermal dendritic cells
What’s the mutation associated w/ Dermatofibrosarcoma Protuberans?
Translocation involving: COL1A1 and PDGFB
- COL1A1: encodes collagen 1A1
- PDGFB: encodes platelet-derived growth factor-B
What’s CTCL?
Cutaneous T-Cell Lymphoma
The specific one we’re referring to is Mycosis Ungoides
What’s Sezary syndrome?
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
What morph eatures are associated w/ Mycosis Fungoides?
Sezary-Lutzner cells (which form bandlike aggregates within superficial dermis
- can invade epidermis as single cells or groups (Pautrier microabscesses)
What is the Mastocytosis we’re studying and what population does it affect?
Urticaria pigmentosa
Children
What’s the Darier sign and what’s it associated w/?
Localized are of dermal edema and erythema (wheal) occurring when lesional skin is rubbed
- urticaria pigmentosa, a Mastocytosis
What’s ichthy Greek for?
Fishy
