Dermatopathology-Fung Flashcards
What are the 3 layers of the skin?
Epidermis
Dermis
Subcu
What is found in the epidermis?
mainly keratinocytes--produce keratin, a water soluble barrier for the skin. stratified squamous cells melanocytes-UV protection. inflammatory cells langerhans cells
What is found in the dermis?
layer filled with collagen
adnexal structures: hair follicles, glands
What is found in the subcutaneous layer? What is its function?
lots of fat!
provides shock absorption
thermal insulation for the skin
What are the layers of the epidermis–from nearest the basement membrane up? Note: this is the same order of keratinocyte maturation.
Stratum Basale.
Stratum Spinosum
Stratum Granulosum
Stratum Corneum
What is the main function of the stratum basale?
responsible for regenerating keratinocytes
What is the main function of the stratum spinosum?
polyhedral keratinocytes
produce cytokeratins–these form tonofibrils & desmosomes.
What is the function of desmosomes? Note: these are partially formed in the stratum spinosum.
function: intercellular bridges
What is the appearance of the stratum granulosum? What is found there? What is its function?
It appears blue
keratohyalin granules are there!
keratohyalin granules combine with tonofibrils=keratin made!
What is found in the stratum corneum?
mature keratin
these keratinocytes don’t have nuclei or cytoplasm. It was spit out!
Which structure separates the epidermis & dermis?
the basement membrane
The epidermis has ridges that connect with the _____ layer of the dermis. What is the function of these ridges?
these ridges help the skin to withstand sheering forces
connects with the papillary layer of the dermis
Which layer is found beneath the papillary layer?
the reticular layer
has collagen bundles!
What are the 2 types of glands that are found in the dermis?
apocrine-non fcnl
secretory/eccrine-secrete sweat!
What is the main function of eccrine sweat glands?
thermoregulation!
Where are the apocrine glands found?
axilla & groin
What is different & special about the skin that is found on the soles of feet & palms of hands?
they have modified skin!
no adnexal structures in the dermis
bunches of thick keratin in the epidermis
can withstand more trauma
What is the macule’s larger buddy?
the patch.
What is the def & distinguishing features of a macule?
Well circumscribed. flat lesion. Less than 5 mm Sharply demarcated from the skin. Noted b/c of pigmentation compared to rest of skin.
What is the definition of a patch?
well circumscribed
flat
>5 mm
different color
What is the definition of a papule?
well circumscribed
elevated dome-shaped or flat-topped lesion
<5 mm
What is the definition of a nodule?
well circumscribed
elevated dome-shaped or flat-topped
>5 mm
What is the papule’s larger buddy?
nodule!
What is the definition of a plaque?
elevated flat-topped lesion >5 mm ex: psoriasis something seen in chronic inflammatory dermatosis
What is the definition of a pustule?
these are pus filled
raised lesions
no size criteria
seen in acne & abscesses
What is the definition of a scale?
dry, horny, platelike excrescence
b/c of imperfect cornification
What is the definition of a vesicle?
fluid-filled raised lesion
less than 5 mm
blister
What is the definition of a bulla?
fluid-filled raised lesion
greater than 5 mm
blister
What is the vesicle’s larger buddy?
bulla
What is the definition of an excoriation?
traumatic lesion breaking the epidermis
causes a raw linear area (deep scratch)
What is the definition of a wheal?
itchy transient elevated lesion
variable blanching
some blistering
erythema–dermal edema present
What is lichenification?
thickened
rough skin
usu result of repeated rubbing
What is acanthosis?
microscopic lesion
diffuse epidermal hyperplasia, thickened
seen in chronic inflammatory dermatosis
What is acanthosis’ friend?
papillomatosis
What is the definition of papillomatosis?
microscopic lesion
thickened epidermis, hyperplasia
distinct papillary fragment
enlarged contiguous dermal papillae
What is hyperkeratosis?
thickened keratin layer
stratum corneum is thickened
no nuclei, like normal
What is the friend of hyperkeratosis?
parakeratosis
What’s the deal with parakeratosis?
microscopic lesion
also a thickened keratin layer
abnormal in that it retains the nuclei in the keratinocytes. see blue dots in the stratum corneum.
What is hypergranulosis?
thickened stratum granulosum
what is spongiosis?
this is when you don’t see much space b/w the keratinocytes, edema has pushed them apart!
basically: intercellular edema of the epidermis
What is lentiginous, a microscopic lesion?
melanin is produced in the epidermal basal layer linearly
What is dyskeratosis?
abnormal premature keratinization due to malignant change
happens below the stratum granulosum, which is abnormal
when you see a bunch of pink in the epidermis
What happens in an acute inflammatory dermatosis?
it lasts from days-weeks
there are lymphocytic & macrophage inflammatory infiltrate & edema.
What happens in chronic inflammatory dermatosis?
months-years
changes in epidermal growth (atrophy or hyperplasia)
or changes in dermis, maybe fibrosis
skin is roughened due to excess or abnormal scale formation & shedding
What is urticaria, hives?
common disorders caused by local mast cell degranulation & dermal microvascular hyper permeability
get pruritic edematous plaques (wheals)
can be acute or chronic
acute if less than 6 weeks
What is angioedema?
condition that is related to urticaria
edema of a deeper dermis & subcutaneous fat
Which is fairly normal in urticaria: epidermis, dermis?
epidermis is fairly normal
papillary dermis exhibits edema
inflammation
What are some possible causes of urticaria?
Causes include Immunologic mechanisms Non-immunologic mechanisms Physical stimuli Skin contact Small vessel vasculitis
What are some treatment options for urticaria?
avoidance of allergen
oral h1 antagonists
epi
What is acute eczematous dermatitis?
common skin disorder
results from t cell mediated inflammatory reactions
type IV DTH
What are the 5 categories of acute eczematous dermatitis?
Allergic contact dermatitis Atopic dermatitis Drug-related eczematous dermatitis Photoeczematous dermatitis Primary irritant dermatitis
What are some microscopic features of acute eczematous dermatitis?
spongiosis: space b/w keratinocytes
parakeratosis: nuclei present in the stratum corneum
sometimes you get intaepidermal vesicles
What are the 2 broad categories of causes of acute eczematous dermatitis?
Inside Cause: internal circulating antigen
Outside Cause: external application of an antigen
What is the treatment of acute eczematous dermatitis?
removal of antigen
topical steroids
What is erythema multiform?
self limited hypersensitivity reaction
associated with certain infections from viruses, bacteria, fungi
associated with exposure to some drugs
associated with cancer & collagen vascular disease
What are some viral infections & bacterial infections associated with erythema multiform?
viral: herpes simplex
bacterial: mycoplasma, leprosy, typhoid
What are some fungal infections associated with erythema multiform?
histoplasma
coccidioides
What are some drugs that a pt can be exposed to and then develop erythema multiform?
sulfonamides penicillin barbiturates salicylates antimalarials
Stevens Johnson Syndrome is a febrile form of ________. with extensive skin involvement.
a form of erythema multiforme
can lead to sepsis
often seen in children
Which additional areas of skin does stevens johnson syndrome include?
oral mucosa
conjunctiva
urethra
genital & perianal regions
Toxic Epidermal Necrolysis is a form of _________. What is it characterized by?
form of erythema multiform
diffuse necrosis, sloughing of cutaneous & mucosal epithelial surfaces
similar clinical case to a burn pt
What is the treatment for erythema multiform? For acute & chronic cases?
Treatment Acute -- Observation Oral antihistamines Topical steroids Acyclovir-in treatment of recurrent herpes. Prednisone Chronic-- Antivirals (acyclovir) Dapsone Azathioprine Cyclosporine
What % of the pop. does psoriasis affect?
1-2%
What is psoriasis?
Chronic inflammatory dermatosis that results from interactions of genetic and environmental factors
Associated with HLA-C
**Results from activated T cells in the skin stimulating the secretion of cytokines and growth factors that induce keratinocyte proliferation
15% of psoriasis patients also have what?
associated arthritis
What is the auspitz sign? Which condition is it associated with?
this is associated with psoriasis. It is when you get micro hemorrhages after scraping off plaques. this is when the b.v. of the papillary dermis reach the epidermis.
Where can you sometimes see monroe abscesses in psoriasis?
within the parakeratosis
What is the treatment for psoriasis?
Treatment Topical steroids Intralesional steroid injection UVB and tar Methotrexate Cyclosporine Soriatane
What is seborrheic dermatitis?
common chronic inflammatory dermatosis affects up to 5% of general pop.
involves regions of high density sebaceous glands
What are some common areas to see seborrheic dermatitis?
remember: areas with sebaceous glands!
Scalp Forehead External auditory canal Retroauricular area Nasolabial folds Presternal area
What are the causes of sebhorreic dermatitis?
increased sebum production
colonization of the skin by Malassezia
can get a more severe form if you are HIV+ & have low CD4 counts
What is the treatment for sebhorreic dermatitis?
Treatment Frequent washing of the affected area with antisebhorreic soaps Topical steroids Anti-yeast medications Oral antifungals
Lichen has 6 letters. So…lichen planus has 6 important Ps. What are they?
- pruritic
- purple
- polygonal
- planar
- papules
- plaques
Describe the resolution process of lichen planus.
it is a self limited condition & resolves spontaneously 1-2 years after onset
resolution of lesions may leave post inflammatory hyper pigmentation
What may develop in oral lesions of lichen planus?
squamous cell carcinoma
What is wickham’s striae? Which condition is it associated with?
these are white lines that are seen within a purple plaque
sign of lichen planus
What causes wickham’s striae?
hypergranulosis
What is the treatment for lichen planus?
Treatment Topical steroids Intralesional steroids Systemic steroids Azathioprine Cyclosporine Light therapy (PUVA & UVB)
Give some examples of conditions that include blisters.
Herpes virus
Spongiotic dermatitis
Erythema multiforme
Thermal burns
What are the characteristics of bullous blistering disorders?
group of diseases with blisters that are primary & distinctive features
inflammatory or not!
Which layer of the skin are the pemphigus foliaceus blisters located?
subcorneal
right underneath the stratum corneum
Which type of blistering disorder has blisters located above the basal layer?
pemphigus vulgaris
Which type of blistering disorder has blisters located below the epidermal layer?
bullous pemphigoid
**occurs below the stratum basal…at the level of the basement membrane
Pemphigus foliaceus which makes sub_____ blisters is directed against which desmoglein?
subcorneal blisters
directed against desmoglein 3
Bullous pemphigoid is directed against what?
BPAG2 at the hemidesmosome level
What is pemphigus?
inflammatory blistering disorder
caused by autoantibodies that result in dissolution of intercellular attachments w/i epidermis & mucosal epithelium.
Which antibodies does pemphigus involve? What do they target?
involves IgG autoantibodies
to desmoglein 1 & 3
**affects desmosomes
What are the 5 variants of pemphigus?
pemphigus vulgaris pemphigus vegetans pemphigus foliaceus pemphigus erythematosus paraneoplastic pemphigus
Which type of pemphigus is associated with cancer?
paraneoplastic pemphigus
Which type of pemphigus is the most common, seen 80% of the time?
pemphigus vulgaris
Which type of pemphigus is seen as plaques around the groin?
pemphigus vegetans
Which type of pemphigus forms sub corneal blisters?
pemphigus foliaceus
Which type of pemphigus forms less severe sub corneal blisters?
pemphigus erythematosus
What would you see on histo of pemphigus vulgaris?
you would still see the basal layer, b/c the blisters are supra basal
see intraepithelial vesicles being formed
What is the proper treatment of pemphigus?
immunosuppressive agents–decrease titers of pathogenic autoantibodies
What is bullous pemphigoid?
blistering disorder (inflammatory) caused by autoantibodies against proteins that bind basal keratinocytes to the basement membrane
What are the proteins that link the basal keratinocytes to the basement membrane?
BPAGs are the proteins that are a critical part of the hemidesmosomes
What is the pattern of antibody deposition in bullous pemphigoid?
linear pattern at the dermoepidermal junction
What happens when you touch the blister of a pt w/ bullous pemphigoid?
they don’t break when touched
they can even heal without scarring
What is the treatment for bullous pemphigoid?
topical steroids
systemic steroids
methotrexate
azathioprine
What is dermatitis herpetiformis?
urticaria & grouped vesicles strong association with HLA-B8, HLA-DR3, HLA-DQw2 develop IgA antibodies to dietary gluten antibodies cross react w/ reticulin injury results in sub epidermal blisters
Why is it that antibodies to reticulin could lead to sub epidermal blisters in dermatitis herpetiformis?
reticulin is a component of anchoring fibrils that attach the epidermal basement membrane to the superficial papillary dermis
What is the treatment for dermatitis herpetiformis?
dapsone
sulfapyridine
**immunomodulatory agents
What is an example of a non-inflammatory blistering disorder?
epidermolysis bullosa
What is epidermolysis bullosa?
inherited defect in structural proteins that cause mechanical instability for the skin
soon after birth see blister formation at sites of pressure, rubbing, or trauma
What are the 4 types of epidermolysis bullosa?
simplex
junctional
dystrophic
mixed
How is the simplex type of epidermolysis bullosa inherited? What does it target?
aut dom inheritance
affects keratin 14 & 5
defects in the basal cell layer of the epidermis
gives sub epidermal blisters!!
What are the 2 components of the basement membrane?
lamina densa
lamina lucida
How is the junctional type of epidermolysis bullosa inherited? What does it target?
aut rec inheritance
born w/ defects in laminin
laminin deficiency–>makes lamina lucida of basement membrane defective.
blisters seen @ the level of the lamina lucida
What does the lamina lucida bind to?
binds to hemidesmosomes
binds to anchoring filaments (bind basal keratinocytes to basement membrane)
How is the dystrophic type of epidermolysis bullosa inherited? What defects are present?
aut dom inheritance or aut rec
defects in type VII collagen
causes blisters at the level of the lamina densa (in the basement membrane)
scarring disorder
What is type VII collagen a major component of?
basement membrane anchoring fibrils
