L2 Intro and skin CA Flashcards
Stratum corneum
superficial layer with shedding dead skin cells
Stratum lucidum
layer found on plantar and palmar surfaces
Stratum granulosum
keratinization
Stratum spinosum
spiny-shaped cells (strength and flexibility)
Stratum basale
cells germinate: keritinocytes
Order of epidermal layers
Come, (Let’s) Get SunBurn
Types of epidermal cells
keratinocytes
melanocytes
merkel cells
langerhans cells
keratinocytes
most common cell in epidermis
form a barrier
in deepest layer they are called basal cells
Langerhan’s cells
Dendritic cells scattered through the epidermis
derived from bone marrow
“macrophages of the skin”
Merkel cells
Mechanoreceptors
abundant in fingertips
Melanocytes
pigmented cells that help protect against UV rad.
Dermis
support structure
contains: blood & lymph vessels, nerves, hair follicles, glands, and fibrous tissue
Layers of the dermis
Papillary
Reticular
Ground substance
Papillary dermis
superficial, loose, fine collagen fibers
Reticular dermis
deep dermis, densely packed & think collagen bundles. elastic fibers
Ground substance
proteoglycans and glycosaminoglycans
Basement Membrane Zone (BMZ)
dermal-epidermal junction two layers: basal lamina reticular connective tissue defects here are the basis for many blistering diseases
Hypodermis (subcutis)
Fibroblasts, adipose, and macrophages
subcutaneous fat
Eccrine glands
covers most of the body releases at the surface of the skin function in temp reg coiled gland in deep dermis (secretion) Straight duct extends to epidermis (transportation)
osmolarity of sweat
begins isotonic with plasma, but electrolyte reabsorption in duct causes it to be hypotonic
apocrine glands
concentrated in axilla and anogenital regions
secretes into the sac of the hair follicle
fluid is odorless when released, bacteria makes it smell rank
driven by adrenaline
vellus hair
short and fine hairs
terminal hair
long and thick hairs
bulb
enlargement at base of hair follicle
Pathogenic mechanisms
ACID Type 1: immediate/allergy Type 2: cytotoxic Type 3: immune complex Type 4: delayed sensitivity
Type 1: immediate
IgE
allergies
mast cells and basophils
Ex: hives, bronchospasm
Type 2: Cytotoxic
Circulating IgG or IgM
react to surface antigen
Type 3: Immune complex
Antigen-antibody complexes are introduced to the tissue causing inflammation
IgG or IgM
Type 4: Delayed sensitivity
cell-mediated immunity
24-48 hours after exposure
curettage
scraping skin away with curette
electrodessication
high freq current applied to lesion, drying it out/burning
cryotherapy
tissue is destroyed using -40°C liquid nitrogen
Punch biopsy
round cookie cutter that cuts through the epidermis, dermis, and subcutis
solar lentigo
age spot/freckle
local proliferation of melanocytes
well-circumscribed margins
no tx required
Seborrheic Keratosis (SK)
common tan-black warty, waxy, "stuck-on", benign epidermal lesion proliferation of immature keratinocytes "barnacles of aging" genetic link to multiple can have Leser-Trelat sign
ISK
irritated SK
may be pruritic, painful, or bleed if rubbed
Leser-trelat sign
christmas tree-like pattern seen in SK, if also assoc with skin tags and acanthosis nigrans, there is a possible association with GI and lung cancers
evaluation and treatment of SK
typically clinical
may bx if needed
reassurance
can be removed if ISK
Keratoacanthoma (KA)
benign
Hallmark: rapid growth over 6-8 weeks
round, flesh colored nodule w/ central keratin plug
KA management
majority resolve spontaneously in 6-9 mo
usually bx before then
difficult to dx
Actinic Keratosis (AK)
aka solar keratosis considered pre-cancer may progress to SCC M>F erythematous, scaly/gritty macule or papule may be tender
Subtypes of AK
hypertrophic (thickened) atrophic (scale absent) cutaneous horn pigmented Actinic cheilitis (lip)
Dx of AK
typically clinical based on visualization and touch
dermoscopy
shave or punch bx to differentiate from SCC
management of AK
may resolve, but could reoccur isolated: cryotherapy or surgical excision multiple: field treatment photodynamic therapy topical 5-fluorouracil imiquimod skin surveillance for SCC progression
skin cancer
most common cancer in the us.
melanoma vs malignant non-melanoma
Basal Cell Carcinoma
BCC most common skin cancer arises from basal cells of epidermis Nodular is most common subtype flesh-colored, pinkish pearly papule/nodule TELANGIECTASIAS central ulceration with rolled border head and neck
BCC tx and prognosis
surgical removal, cryotherapy, radiation, if superficial can use 5% FU cream metastasis is rare may recur locally invasive
Squamous Cell Carcinoma (SCC)
2nd most common skin cancer males 50-70 immunosuppressed may arise in area of previous skin injury that doesn't heal papule, plaque, nodule pink, red, skin colored might be pruritic or tender scaly, exophytic, indurated, friable appears warty/hyperkeratotic no defined border, vessels, or pearly color
SCC tx
surgical
wide excision with clear margins, MOHS, curettage and cryotherapy
non-surgical
radiation if poor surgical candidate
if SCC in situ: creams, gels, phototherapy
SCC prognosis
rate of metastasis is 5%
increases if lesion is >2cm diameter and >4 mm deep or recurrent
surveillance every 3-6 mo for 2 yrs then 6-12 mo for 3 years, then annually
MOHS
complete margin analysis
higher cure rates
spares normal tissue
costly/long procedure
Excisional bx
fast, cheap
higher recurrence rate
can be done by more providers
Malignant melanoma (MM)
3% of skin cancers avg age at dx is 40 risk factors: >5 atypical nevi, >25 nevi immunosuppression personal/family hx UV asymptomatic mostly new lesions (de novo) some from pre-existing nevus pigmented papule/nodule ABCDE
Melanoma subtypes
superficial spreading
nodular
lentigo maligna
Acral lentiginious
superficial spreading melanoma
most common subtype of melanoma confined to epidermis younger pop radial>vertical spread men: backs women: back and legs
nodular melanoma
rapid vert growth
minimal radial growth
agressive
inflamed and friable nodule
lentigo maligna melanoma
elderly with chronic sun exp
slow progression radially with rapid vertical growth
typically more superficial
acral lentiginous melanoma
darker skin spreads superficial then vertical M>F larger lesions due to delay in dx palmar, plantar, subungual
subungual melanoma
great toe or thumb
hx of trauma
dark streak involving proximal nail fold
amelanotic melanoma
minimal or absent pigment
extensive ddx: psoriasis, dermatitis, BCC, SCC
Treatment of Melanomas
wide surgical excision is gold standard with 2 cm clear margins depending on depth and tumor size
possible lymph node bx
follow up every 3 months
