1.1 Pathology of Skin (pt 1) Flashcards
what is the deadliest of all skin cancers?
provide characterisitics!
malignant melanoma
strongly associated w/ sun exposure
inherently immunogenic (T-cell)
(mutation = cell cycle regulator: p16/INKa, CDK4), growth factor receptors - RAS, BRAF & telomerase)
= vary color, large, irregular, hetergenous, notched borders, pigment incontinence
what is mastocytosis
and what is an example
spectrum of rare disorders due to increased number of mast cels in skin & maybe other organs
-ex: urticaria pigmentosa: predominate in children; could be nodular, diffuse &/or multiple
10% of ind w/ mast cell dz have systemic dz (ex adults: kit mutation in systemic mastocytisis)
What are the ABCDEs of Melanoma
(what does a normal mole look like?)
A: asymmetry
B: border
C: color
D: diameter
E: evolving
normal mole = brown/tan, flat/raised, round/oval, <6mm
what is the difference btn papule and nodule
both - elevated dome shaped/ flat topped lesion
papule = 5 mm
nodule = >5mm
provide the following for Cowden syndrome:
inheritance pattern
chromosomal location/gene/protein
fxn/manifestation of loss
inheritance pattern: AD
chromosomal loaction/gene/protein: 10q23/ PTEN/PTEN
fxn/manifestation of loss = trichilemmomas (lipid phosphatase/benign follicular appendage tumor) & internal adenocarcinoma (breast & endometrial)
how common are skin conditions in the US?
very common!
affect 1/3 of US population
what are examples of tumors of the dermis
benign fibrous histocytoma (dermatofibroma)
Dermatofibrosarcoma protuberans
explain the difference btn epidermal ridges and demal papillae
epidermal ridges (aka rete ridges) that project into the dermis *look different based on location*
dermal papillae - project into the epidermis
What is dermatofibrosarcoma protuberans
= primary fibrosacroma of the skin
==> translocation COL1A1 (collagen 1A1) & PDGF-B –> overexpress PDGF-B –> tumor cells growth through an autocrine loop
= encapsulated, cellular (could involve fat), slow growing & locally aggresive - rarely metastasize
*Storiform pattern (last pic) ; closely packed fibroblasts arranged radially (pinwheel appearance)
This shows a stain that positively stained fro the melanocytic marker, what is the marker?
HMB-45
how do actinic keratosis present histologically
atypical basal cells- pink/red cytoplasm
Intercellular bridges present (not in BCC!)
Parakeratosis - thickened stratum corneum that retain their nuclei
Elastosis: thick, blue-gray elastic fibers of superficial dermis
BM intact (not in SCC!)
how does the basillar layer mature?
bottom to top
columnar cuboidal –> stellae
what is lentigo
localized, circumscribed melanocytic hyperplasia (linear, non-nested)
–>infancy & childhood
-DO NOT darken w/ sun
provide the following for familial melanoma syndrome:
inheritance pattern
chromosomal loaction/gene/protein
fxn/manifestation of loss
inheritance pattern: AD
chromosomal loaction/gene/protein: 9p21 - CDKN/p16/INK4 or CDKN2/p14/ARF
fxn/manifestation of loss: melanoma
what are the disorders of pigmentation and melanocytes
freckles (ephelis)
lentigo
melanocytic nevus
dysplastic nevi
melanoma
how do actinic keratosis present?
who is most suseptible
elderly
= prolif of keratin process make horn (aka hyperkeratosis)
=tan, brown, red or flesh colored < 1cm
what is the word for thickening of the stratum corneum bc qualitative abnormality of keratin
hyperkeratosis
provide the following for Tuberous sclerosis:
inheritance pattern
chromosomal loaction/gene/protein
fxn/manifestation of loss
inheritance pattern: AD
chromosomal loaction/gene/protein: 9p34/TSC1/hamartin & 16p13/TSC2/tuberin
fxn/manifestation of loss: (-)ly regulate mTor, angiofibroma, mental retardation
what is the morphology for acanthosis nigricans
epidermis and underlying enlarged dermal papillae undulate sharply and make numerous peaks/valleys
see hyperplasia, hyperkeratosis & slight basal cell layer hyperpigmentation
what is scale
dry, horny, platelike outgrowth
result from imperfect cornification
Describe the pathogenesis, morphology, presentation of BCC
*rmr BCC = most common invasive CA in humans & most common malignancy worldwide BUT metastasis is rare*
pathogenesis: uncontrolled hedgehog signaling - PTCH LOF mutation
morphology: basal cell prolif; 1. multifocal growth from epidermis & 2. nodular lesion growing downward into dermis ad cords and islands of basophilic cells w/ hyperchromic nuclei
palisading - cells in periphery of tumor cell islands tend to be arranged radially w/ long axes in parallel alignement
present: pearly papules w/ telangictasia, elevated & translucent w/ some sort of central umbilication
define/describe (presentation & microscopicaly):
seborrheic keratoses
= common, benign epidermal tumor; common in elderly
=pigmented or pale/irritated (only bc ppl pick at skin) ; mostly on the trunk, superficial, flat, round/coin-like
=waxy exophytic lesions (stucco keratosis) crumble/scrape off
pseudohorn cysts- keratin on surface- rete pegs proliferate and highly pigmented
what are the components of epidermis
(epidermis = most superficial)
=stratified squamous epithelium
squamous epithelial cells (keratinocytes)
melanocytes
dendritic cells
merkel cells
define excoriation
traumatic lesion breaking the epidermis - cause raw linear area
what is the pathogenesis and morphology of melanocytic nevus
pathogenesis: activating mutation in BRAF, less often NRAS
Morphology:
- junctional : flat; nest of nevus cells at dermoepidermal jxn (common in kids) - larger cells & produce melanin
- compound: rounded/raised; nests/cords of melanocytes that extend into underlying dermis - smaller, produce little pigment
older adults: intradermal nevi
what is onycholysis
separation of nail plate
what is Leser Trelat sign?
sudden appearance of multiple seborrheic keratosies & paraneoplastic syndrome
b/c keratnocyte stimulation via TGFalpha made by visceral cancers
what is the mnemonic for painful skin lesions
GLEN-DAB
Glomus tumor (typically under nail)
Leiomyoma (angio-type)
Eccrine spirademona
Neurofibroma
Dermatofibroma
Angiolipoma
Blue rubber bled nevus