Chapter 25: The Skin Flashcards Preview

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Flashcards in Chapter 25: The Skin Deck (69)
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What are Macules (Patch), Papules (Nodule), and Vesicles (Bulla)?

Macules - flat lesion distinguished by surrounding color
- macule < 5 mm
- patch > 5mm

Papule - elevated dome or flat-topped lesion
- papule < 5 mm
- nodule > 5 mm

Vesicle - (blister); fluid filled, raised lesions
- vesicle < 5mm
- bulla > 5 mm


What is Acanthosis, Dyskeratosis, Hypergranulosis, and Hydropic Swelling?

A: diffuse epidermal HYPERplasia

D: abnormal keritinization BELOW the stratum granulosum

H: stratum granulosum HYPERplasia (rubbing)

HS: intracellular keratinocyte edema (viral infections)


What is Hyperkeratosis, Lentiginous, Papillomatosis, and Parakeratosis?

H: stratum corneum thickening

L: linear melanocyte proliferation within basal cell layer

P: surface elevation --> dermal papillae hyperplasia

PK: stratum corneum keratinization w/RETAINED NUCLEI (normal on mucus membranes)


What are the levels of the epidermis from superficial to deep?

Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale

"Californians Love Gorillas in String Bikinis"


What is the Darier Sign, Stevens-Johnson Syndrome, and Auspitz Sign?

DS: dermal edema/wheal formation after rubbing lesion in mastocytosis

SJS: febrile form of erythema multiforme

AS: punctate bleeding in psoriasis when scale is lifted


What is the difference between Freckles, Cafe Au Lait spots, and Lentigo?

F: MOST COMMON pigmented lesion of childhood
- appear AFTER sun exposure (norm. melanocytes)
- focal melanin overproduction

- larger than freckles; INDEPENDENT of sun exposure
- aggregated melanosomes

L: benign, linear melanocytic hyperplasia
- restricted to cell layer ABOVE basement membrane
- do NOT darken with sun exposure


What is are Melanocytic Nevi and how are they generated?

- pigmented moles caused by acquired mutations of RAS or BRAF; leads to period of proliferation that is turned OFF by P16/INK4a

- rarely gives rise to melanoma, although melanomas have disrupted P16/INK4a inhibition


What is the difference between a Junctional, Compound, and Intradermal nervus?

J: nests of nevus cells at dermoepidermal junction
- seen in kids

C: nests/cords of melanocytes into DERMIS
- looks like neurological tissue (BENIGN)

I: complete loss of nests
- prominent during pregnancy


What is the difference between:

Black Nevus
Spindle/Epithelioid Cell Nevus
Halo Nevus
Dysplastic Nevus

BN: black-blue nodule (non-nested dermal infiltration)
- confused with MELANOMA

SCN: red-pink nodules; fusiform cells
- confused with HEMANGIOMA (common in kids)

HN: identical to acquired nevi but with lots of T-Cells
- lymphocytic infiltrate present

DN: coalescent intraepidermal nests; cyto ATYPIA
- potential precursor of MELANOMA


What is a Dysplastic Nevi and what mutation is associated with it? (Dysplastic Nevus Syndrome)

- compound nevi with cytological/architectural atypia, lentiginous hyperplasia, and linear papillary dermal fibrosis (usually develop hundreds of dysplastic nevi)

- usually flat macules that are > 5mm and LARGER than acquired nevi

- AUTO DOMINANT mutation causes loss of CDKN2A (encodes p16/INK4a) = activated RAS/BRAF


What is the most deadly of all skin cancers? What type of radiation usually causes it?


- usually due to UV radiation (worst is UVB) exposure but also some from AUTO DOMINANT inheritance


What are the two most common areas for melanoma to arise in females and males?

F: back and legs
M: upper back

**BANL - back, arms, neck, legs**


What are 3 of the most common mutations that occur in Melanoma tumors?

- inhibition of CDKN2A

- activation of BRAF or KIT (usually KIT)

- activation of TERT (telomerase)


What is the difference between Radial Growth and Vertical Growth of melanoma?

What is the Breslow Thickness Scale?

Radial: horizontal spread in epidermis/sup. dermis
- unable to metastasize
- 3 classes

Vertical: dermal invasion of cells lacking cellular maturation (has metastatic potential)
- increases as the depth of penetration increases

BTS: distance between granulosum layer to deepest intradermal tumor layer
- < 1 mm of invasion = 95-100% 5 yr survival
- > 4 mm of invasion = 37-50% 5 yr survival


What are the ABCDEs of Tumor Identification?

A - asymmetry
B - borders (irregular or regular)
C - variegated color
D - increasing diameter (concern > 6mm, most at 10)
E - evolution (change over time)


What are the 3 classes of Radial Growth melanomas? (LM/SSM/AL)

1. Lentigo Maligna
- indolent, older men, BEST prognosis

2. Superficial Spreading Melanoma
- MOST COMMON of the subtypes
- horizontal growth, stuck in radial phase for awhile

3. Acral Lentiginous
- usually on Black/Asian extremities (soles/palms)
- due to C-Kit mutation (treat w/imantinib)


What is Seborrheic Keratoses, what mutation does it carry, and what sign is associated with it?

- common/spontaneous/benign epidermal tumor of the trunk, extremities, head/neck

- round, flat, coin-like waxy plaques (tan-brown and velvety)

Mutation: FGFR3 activating mutation

Sign: Leser-trelat Sign (inc. keratinocytes - inc. TGFa)
- sudden appearance of multiple seborrheic keratoses
- also paraneoplastic syndrome (think visceral cancer)


What is Acanthosis Nigricans, what mutation does it carry, and what is it commonly associated with?

- thickened hyperpigmented skin w/velvety texture see in FLEXURAL areas

- prominent rete ridges, basal hyperpigmentation, hyperkeratosis WITHOUT melanocyte hyperplasia

- most are benign, but most common association is with OBESITY and DIABETES (IGFR-1 activates same pathway as FGFR3)

Mutations: familial (Auto Dominant: FGFR3) OR hyperinsulinemia (inc. IGFR1 signaling)


What are Fibroepithelial Polyps (SKIN TAGS), what do they look like, and what are they associated with?

- common cutaneous legion and are mostly sporadic

- soft, flesh-colored tumors attached by slender fibrovascular STALK (benign epidermis)

- usually inconsequential but normally associated with DM, obesity, or intestinal polyposis (also inc. in number during pregnancy)


What is the difference between an Epithelial/Follicular Inculsion Cyst and and Adnexal (appendage) Tumor?

FIC: cystic expansion of epidermis/hair follicle
- can lead to extensive/painful granuloma formation
- STINKY (filled with keratinaceous material)

AT: nondescript, fleshy nodules or papules (BENIGN)
- primarily affect apocrine glands (scalp/axilla)


What is Actinic Keratosis, what is Actinic chelitis, and what can Actinic Keratosis progress to?

- hyperkeratosis of sun damage leading to cutaneous horns (exuberant keratin production of face/arms/dorsum of hands)

- exhibit Parakeratosis, atypical basal cells, intracellular bridges

AC = cutaneous horns of the lip

- can progress to cutaneous squamous cell carcinoma


What is Squamous Cell Carcinoma, what causes it, and what 3 mutations can it have (T/R/N)

- 2nd most common tumor of sun exposed skin, usually occurring in males with < 5% chance for LN metastasis

- biggest risk factor is LIFETIME exposure to sun, usually developing from Actinic Keratosis (sun damage) but can also be caused by immunosuppression (HPV5/8)

mutations: TP53 (inc. pyrimidine dimers and error prone repair), RAS and NOTCH signaling mutations


What is the difference between In Situ and Invasive Squamous Cell Carcinoma?

IS: well-demarcated, red, scaling plaques

ISSC: NODULAR, ranges from well differentiated to highly anaplastic with necrosis/ulceration


What is Xeroderma Pigmentosum?

- auto recessive mutation of nucleotide excision repair of pyrimidine dimers

- defective excision repair = error prone repair

- usually seen in YOUNG pts with skin cancer


What is Basal Cell Carcinoma, what mutation does it have, and what does it look like?

- most common invasive cancer and malignancy worldwide; slow growing and aggressive, but very RARELY metastasize

mutation: PTCH LOF = uncontrolled Hedgehog signaling

- has pearly papules with telangiectatic vessels; nodules extend deeply into dermis as islands/cords of basophilic cells with hyperchromatic nuclei (PALLISADING)


What is Nevoid Basal Cell Carcinoma Syndrome and what mutation does it have?

- aka Basal Cell Nevus or Gorlin Syndrome, usually seen in those < 20 yo

- autosomal dominant mutation --> PTCH LOF mutation causing transcription factor GLI1 = tumor growth

- 1/3 have pyrimidine dimers


What are the 2 tumors of the Dermis? (FH/DP)

Fibrous Histiocytoma (dermatofibroma) = BENIGN

Dermatofibrosarcoma Protuberans = MALIGNANT


Fibrous Histiocytoma (Dermatofibroma)

What is it and what does it look like?

- benign dermal neoplasms w/Factor XIIIa (+) dermal dendritic cells occurring on legs of young females

- firm, brown/tan papules with spindle-like fibroblasts in a well-defined non-encapsulated mass

- also see pseudoepitheliomatous hyperplasia (downward elongation of hyperpigmented rete ridges)


Dermatofibrosarcoma Protuberans

What is it, what mutation is it associated with, and what does it look like (2)?

- slow, locally aggressive primary fibrosarcoma of the skin

- translocation of COL1A1 and PDGFb causing overexpression of PDGFb = autocrine loop growth

- has storifrom pattern (closely packed fibroblasts arranged radially = PINWHEEL) and honeycomb pattern (extension into SubQ FAT)


Mycosis Fungoides

What is it, what does it look like, and what two cells are hallmarks of it (SZC/PM)

- homing CD4+ T helper cell lymphoma that can evolve to Sezary Syndrome (seeding of blood by malignant T cells = systemic)

- scaly red-brown patches on the trunk with FUNGATING Nodules (confused with psoriasis)

- Sezary Lutzner cells (malignant T cells with cerebriform nuclei) and Pautrier microabscesses (bandlike aggregates within superficial dermis)