CHAPTER: Derm

Question 1

What type of lesion is Leser Trelat lesion? What associated disease should you be thinking of?

Answer 1

Seborrheic ketatosis - multiple of these dark, stuck on type skin lesions (vs singular)
“Squamous cell proliferation”
Think underlying cancer - GI tract

Question 2

Exposure to vinyl chloride and arsenic puts you at risk for what type of liver pathology

Answer 2

Angiosarcoma

Question 3

Bartonella henselae and Kaposi look the same on the skin - what’s the difference cell-wise

Answer 3

Kaposi = virus so lymphocyte infiltrate 
Bartonella = bacteria so will be neutrophils

Question 4

What is a strawberry/capillary hemangioma? Vs cherry?

Answer 4

Babies get this raised, red lesion
= unencapsulated group of thin walled capillaries
Initially may grow in size
Will REGRESS ON OWN - don’t treat
Cherry = benign capillary prolif in old people

Question 5

What is the non pussy rash caused by S.pyogenes that has well demarcated borders?

Answer 5

Erysipelas (red oven mits) - well defined red rash (not confined to hands)

Question 6

What is the difference between Staph scalded skin syndrome vs toxic epidermal necrolysis

Answer 6

SSS: bacterial exotoxin destroy stratum granulosum only, sloughing of upper layers of skin, will heal completely
TEN destroys D/E jxn - target lesions (erythema multiforme) that also involves mucous membranes

Question 7

Describe location + bug causes hairy oral leukoplakia

Answer 7

EBV - lateral tongue white plaques, can’t scrape

Vs thrush scrapable

Question 8

Skin manifestation of gastric adenocarcinoma

Answer 8

Acanthosis nigricans - think, dark patches under arms or on neck
Also skin presentation of DIABETES

Question 9

Name Ab for pemphigus vulgaris, bullous pemphigoid, dermatitis herpetiformis

Answer 9

PV = IgG vs desmoglin (desmosome of strat spinosum) "net like" IF + ORAL involvement
BP = IgG vs hemidesmosomes (E/D jxn) linear IF
DH = IgA @ dermal papillae, cross rxn of celiac

Question 10

Skin manifestation of Hep C

Answer 10

Lichen planus - sawtooth lymphocytes @ E/D jxn
6Ps
1. Pruritic
2. Purple
3. Polygonal 
4. Planar (flat)
5. Papules
6. Plaques

Question 11

3 major risk factors for SCC vs 1 big one for basal cell

Answer 11

SCC - UVB light esp if have RF of:
1. Chronic inflam
2. Immunosuppression
3. Arsenic 
Basal - UVB light -> pyrimidine dimers, esp problematic for xeroderma pigmentosum (no NER)

Question 12

2 “precursor” lesions for SCC

Answer 12

Actinic keratosis = dysplasia aka pre-cancer, rough red/brown plaques
Keratoacanthoma - SCC that grows fast and also regresses fast on own (cup w/ debris)

Question 13

Tumor marker, possible mutation (+ associated chemo), and 4 types of melanoma

Answer 13

MELANOMA
S 100
1st choice = resection, if can’t and pt is BRAF V600E + could use vemurafenib (BRAF kinase I)
1. Superficial - radial
2. Lentigo maligna - radial
3. Nodular - vertical
4. Acral (foot) lentiginous - palms + soles, higher risk dark skinned people, NOT related to UV light exposure

Question 14

Describe what a basal cell cancer looks like gross + histo

Answer 14

Ulcer center + rolled edges
Surrounding telang aka easily seen BVs
Histo: large purple cells in epi w/ palasading nuclei on edges

Question 15

What type of HST rxn is eczema?

Answer 15

T1 HST aka allergic rxn w/o direct stimulus - atopic dermatitis

Question 16

What makes a freckle :)

Answer 16

↑# melanosomes in normal # melanocytes

Question 17

Biochem pathway that melanocytes make melanin

Answer 17

Tyrosine (tyrosine OH) -> dopa -> -> (tyrosinase) = melanin

Question 18

What is albinism vs melasma vs vitiligo

Answer 18

A: X tyrosinase or tyrosine transport so can’t make melanin
M: preg or OCP causes face hyperpig rash
V: AI destruction of melanocytes
1. Black people with spots of white
2. White people with areas that don’t tan

Question 19

Name the 5 layers of epithelium

Answer 19

Corneum (no nuclei)
Lucidum
Granulosum - looks like granules inside
Spinosum attached by desmosomes 
Basale = stem cells