ICL 1.3: Dermatopathology Flashcards
what are the types of inflammatory dermatoses?
- acute
- chronic
- blistering diseases
- disease of appendages
- fibrosing dermopathy
- panniculitis
- vasculitis
which inflammatory dermatoses are acute?
- urticaria
- spongiotic dermatitis
- erythema multiform
which inflammatory dermatoses are chronic?
- lichen planus
- lupus
- psoriasis vulgaris
which inflammatory dermatoses are blistering diseases?
- pemphigus vulgaris
- bullous pemphigoid
- dermatitis herpetiformis
which inflammatory dermatoses are diseases of cutaneous appendages?
acne vulgaris
which inflammatory dermatoses are fibrosing dermopathy?
scleroderma
which inflammatory dermatoses are panniculitis?
erythema nodosum
which inflammatory dermatoses are vasculitis?
leukocytoclastic vasculitis
what is urticaria?
an acute dermatoses that is a type I hypersensitivity reaction
so most of it is IgE mediated but others can cause direct mast cell degranulation
what happens is that an allergen binds to a cell that has been sensitized by IgE which then leads to mast cell degranulation –> histamine release –> vasodilation –> edema
hallmark = wheal!! aka hive! –> individual wheals persist less than 24 hours, but new lesions develop
what histological findings are consistent with urticaria?
- dermal edema
- EOSINOHPILS
- PMNs in capillaries
what is spongiotic (eczematous) dermatitis?
it’s an acute dermatoses that is the most common dermatitis!!
- atopic, contact, nummular eczema
- pityriasis rosea
- seborrheic dermatitis
- drug eruption
**it is a cause of erythroderma = total body erythema and scaling
where can spongiotic dermatitis be observed on the body? what will it look like?
the site depends on the type of of spongiotic dermatitis
- atopic –> flexural surfaces: elbow, knees, etc.
- seborrheic –> scalp, T-zone, intermammary, axilla
- irritant/contact –> at the site of contact
the clinical appearance then depends on the age of the lesion
- acute = erythematous, moist papules/vesicles
- subacute = erythematous, scaly papules/plaques
- chronic = lichenified plaques
what are some examples of spongiotic dermatitis?
contact dermatitis = poison ivy, allergy to soaps, detergents, deodorants, etc.
which three dermatoses can cause erythroderma?
- psoriasis vulgaris
- spongiotic dermatitis
erythroderma = total body erythema and scaling
- cutaneous T-cell lymphoma
what is the pathology of spongiotic dermatitis?
- Ag contacts epidermis
- Ag picked up by LC
- LC/Ag migrates to LN
- LC presents Ag to CD4+ T cell
- sensitized T cells go to affected area and do cytokine release, more inflammation, edema into epidermis
this all leads to spongiosis +/- vesicles
what histological findings are consistent with spongiotic dermatitis?
- extensive spongiosis = increased intercellular edema
2. epidermal acanthosis = increased thickness of the spinous layer of the epithelium
what is erythema multiforme?
it’s an acute dermatoses that is a hypersensitivity reaction
it’s an interface injury so there is damage to the basal layer and you will see necrotic keratinocytes
the epidermal injury will be out of proportion to the amount of inflammation seen!
usually skin involvement only; no systemic symptoms and caused by HSV
what are the stages of erythema multiforme?
- erythema multiforme
- stevens-johnson syndrome
- toxic epidermal necrolysis (TEN)
what is stevens-johnson syndrome?
a progression of erythema multiforme that involves the skin AND mucous membranes
usually due to medications or mycoplasma
looks like vampire child lips…
what is toxic epidermal necrolysis?
a progression of erythema multiforme that is the most severe end of the spectrum and involves TOTAL skin sloughage; they literally look like burn patients…
usually due to medications
histologically, the epidermis is literally peeling off and totally disattached from the dermis underneath
what are some of the causes of erythema multiforme?
- medication
- herpes simplex virus
- mycoplasma
- collagen vascular diseases
- malignancies (lymphoma, carcinoma)
what are lichenoid dermatoses? which diseases are lichenoid dermatoses?
a chronic dermatoses that involves:
- vacuolar basal layer damage
- eosinophilic necrosis of keratinocytes
- band-like lymphocytic infiltrate**
ex. lichen planus and lupus erythematosus
what is lichen planus?
a lechenoid dermatoses which means it’s chronic and there is vacuolar basal layer damage, eosinophilic necrosis of keratinocytes and *band-like lymphocytic infiltrate
the sites effected are skin or mucous membranes often on extensor surfaces, oral mucosa, genitalia +/- scalp
the lesions are usually symmetrical = on BOTH elbows, wrist, knees, etc.
what is the appearance of lichen planus?
5 Ps = pruritic, polygonal, purple, papules AND plaques*
the lesions will heal with hyperpigmentation because of destruction of the basal layer which is what houses melanocytes!
Koebner phenomenon = new lesions develop at sites of injury
what is Koebner phenomenon?
when new lesions develop at sites of injury
seen in lichen planus
what is the pathology of lichen planus?
possibly a delayed hypersensitivity reaction but we don’t really know….
so maybe there is an unknown antigen in basal cells that causes the lymphs to destroy the basal cells and leads to vacuolar/dropic degeneration = intracytoplasmic accumulation of water
what are the histological findings consistent with lichen plus?
- colloid/Civatte bodies (swollen cells)
- squamatization of basal layer
- pigment incontenence = loss of melanin into dermis which leads to hyperpigmentation
- hyperkeratosis, hypergranulosis and acanthosis following injury of the epidermis
what are the 3 subtypes of lupus erythematosus?
- systemic LE = skin + other organs
- subacute LE = skin +/- other organs
- discoid LE = skin only
what’s the hallmark symptom of systemic lupus erythematosus?
malar rash = butterfly rash
what’s the hallmark symptom of subacute lupus erythematosus?
annular plaques
they have build up borders with scales
what are the hallmark symptoms of discoid lupus erythematosus?
- follicular plugging = yellow looking dots which are hyperkeratosis at the follicular opening
- erythematous plaques
- hypo and hyperpigmentation
scarring happens open and discoid LE especially effects the head and neck
what is the pathogenesis of lupus erythematosus?
it’s an autoimmune reaction to basal keratinocytes (as well as other end organ targets) which leads to:
- hydropic degeneration
- keratinocyte necrosis
- BM thickening
- pigment incontinence –> hyperpigmentation because the basal membrane is being destroyed and it houses melanocytes
- dermis develops vasodilation and edema (lots of while on LM)
what is follicular plugging?
a symptom of discoid lupus erythematosus
it’s when initial injuries cause reactive hyperkeratosis, especially in the follicles which leads to follicular plugging
what immunofluorescence findings are consistent with lupus?
granular IgG and C3 along DE junction (BM) = lupus band test!
with discoid LE, the lupus band test will only be positive in lesional skin only!!
with systemic and subacute LE, the lupus band test will be positive in both lesional and non-lesional skin
what is psoriasiform?
a chronic dermatoses with regular elongation and widening of the rete ridges
ex. psoriasis
what is psoriasis vulgaris? what patient population does it effect?
a type of psoriasiform = chronic dermatoses with regular elongation and widening of the rete ridges
onset is in early adulthood and there is an HLA association
may be associated with arthritis
what are the symptoms and lesions associated with psoriasis vulgaris?
- erythematous, well-demarcated plaques with silver scale often on extensor surfaces and symmetrical
- nails have pitting and oil-spots
- Koebner phenomenon = new lesions develop at sites of injury
- can cause erythroderma =
total body erythema and scaling
which two dermatoses can cause Koebner phenomenon?
- psoriasis vulgaris
2. lichen planus
what is the pathogenesis of psoriasis vulgaris?
it’s unknown, we have no idea why it happens but it’s probably an immune related response that causes keratinocytes to proliferate extremely fast
this causes you to lose the normal appearance of the stratum corneum since the cells retain their nuclei since they’re proliferating so fast
there is regular acanthosis and elongation and widening of rete ridges and dermal papillae
what histologic findings are consistent with psoriasis vulgaris?
- parakeratosis = retained nuclei in the stratum corneum
- hypogranulosis = basically no granular cell layer
- supra papillary plate thinning
- PMNs migrate into the epidermis and stratum corneum = Munro’s microabscesses
what is the hallmark sign of psoriasis vulgaris?
Auspitz sign
this is pinpoint bleeding if the skin is scratched
it happens because of suprapappillary plate thinning – so the dermal papilla are delegated and the epidermis is so thin so when you scratch the capillaries in the papilla just bleed
how are blistering diseases classified?
they are classified according to histologic level of the split
so where in the epidermis do they split down to?
ex. sub corneal, supra basal, subepidermal etc.
what is a routine biopsy vs. an immunofluorescence biopsy?
routine biopsy needs to be from lesional skin – but take it from the edge of the blister not the center (duh)
biopsies for immunofluorescence should be taken from perilesional skin so not the actual blister but right next to it
what is pemphigus vulgaris? what patient population does it effect?
a blistering dermatoses that effects middle aged people
the blisters are often at sites of pressure and oral lesions are also common!!
the blisters are *flaccid vesicles/bullae so they rupture easily and can therefore lead to superficial erosions
since the blisters rupture so easily and exposure the skin, this skin condition could be potentially fatal due to the high risk of infection
what is the hallmark sign o pemphigus vulgaris?
Nikolsky sign
pressure on edge of blister causes blister to expand in the direction of where you put pressure
what’s the pathogenesis of pemphigus vulgaris?
it’s an autoimmune disease where IgG targets desmoglein 3, an intercellular cadherin
desmogleins are the transmembrane proteins in macula adherens junctions aka desmosomes!!
what histological findings are consistent with pemphigus vulgaris?
- acantholysis = loss of intercellular connections in spinous layer
- suprabasilar vescile
what immunofluorescence findings are consistent with pemphigus vulgaris?
intercellular IgG between spinous keratinocytes
it’s a net-like pattern (really does look like a net)
what is bullous pemphigoid? what patient population does it effect?
a blistering dermatoses that is usually self-limited and effects middle aged to elderly people
it effects the skin and mucous membranes just like pemphigus vulgaris but it tends to effect mucous membranes less than PV
effects sites of friction = inner thighs, AC fossa, axillae, groin, etc.
the blisters are tense bull (tight), sub epidermal, filled with clear fluid and heal without scarring