Pathoma skin Flashcards
Name the layers of the epidermis
Stratum basalis (stem cell layer) Stratum spinosum (desmosomes connect) Stratum granulosum (granules in keratinocytes) Stratum corneum (anucleate cells)
Are there blood vessels in the epidermis?
NO! They are all in the dermis!
- pruritic, erythematous, oozing rash with vesicles and edema,
- often involves face and flexor surfaces
- type 1 HSR associated with asthma and allergic rhinitis
Atopic dermatitis (eczema) (treat with topical steroids)
pruritic, erythematous, oozing rash with vesicles and edema after exposure to an irritant
contact dermatitis (treat with topical steroids if needed)
Name lesions associated with acne vulgaris
comedones, pustules, nodules
what is the difference between a whitehead and blackhead?
Closed vs. open comedone
What causes acne?
Chronic inflammation of hair follicles and sebaceous glands; P acnes infection leads to inflammation (pustules or nodules)
Why do vitamin A derivates help with acne?
Reduce keratin production
- Well-circumscribed, SALMON-colored plaques with silvery scales usually on extensor surfaces and scalp (may also have pitting of the nails)
Psoriasis
How would you describe the lesions associated with psoriasis and where do they generally occur?
- Well-circumscribed, SALMON-colored plaques with silvery scales usually on extensor surfaces and scalp (may also have pitting of the nails)
What causes psoriasis?
excessive keratinocyte proliferation, possible autoimmune etiology, associated with HLA-C, often occurs in areas of trauma
What histologic features are associated with psoriasis
Hyperplasia with increased thickness of epidermis (akanthosis); parakaretosis; monroe micro abscesses, elongated dermal papillae, thinned dermis (–> pinpoint bleed = Auspitz sign)
Pinpoint bleeds make you think?
Psoriasis
Treatment for psoriasis
corticosteroids
UV light with psoralen (PUVA)
immune modulating therapy
Pruritic, planar, polygonal, purple papules
Lichen planus
Which what 5 Ps is lichen planus associated?
Pruritic, planar, polygonal, purple papules
What disease is associated with reticular white lines on surface (Wickham striae)?
Lichen planus
Where does lichen planus usually show up?
wrists, elbows, oral mucosa
Key histo finding with lichen planus?
inflammation (lots of neutrophils) at dermal-epidermal junction –> saw-tooth appearance
With what disease is lichen planus associated?
Chronic hepatitis C virus infection
- autoimmune destruction of desmosomes
- due to IgG antibody against desmoglein
Pemphigous vulgaris
- IF highlights IgG surrounding keratinocytes (“fish net”)
Pemphigous vulgaris
Fancy name for scale
hyperkeratosis
“Too much stratum corneum because it is being made too quickly”
Hyperproliferative hyperkeratosis
“Too much stratum corneum because it is being made improperly (leading to clumping/poor sloughing,etc.)”
Retention Hyperkeratosis
congenital lack of pigmentation due to an enzyme defect, usually tyrosinase, that impairs melanin production; may involve eyes (ocular form) or both eyes and skin (oculocutaneous form); increased risk of skin cancer
albinism
Are there increased melanocytes in a freckle?
NO
Are there increased melanosomes in a freckle?
YES
Why are freckles darker than surrounding skin?
INcreased number of melanosomes
Hair growing from a dark spot?
NOT A MELANOMA!!! (most likely a nevus); means cells are “respecting the follicle”
What are the types of nevi?
Junctional (along the DE jxn)
Compound (DE jxn and dermis)
Dermal (dermis only)
Risk factors for melanoma?
Prolonged exposure to sunlight (UVB light)
albinism
XP
Dysplastic nevus syndrome
What are the ABCDEs of melanoma?
Asymmetry Borders irregular Color not uniform Diameter > 6 mm Evolution
What are the growth phases of melanoma?
Radial growth phase (epidermus and superfical dermis)
Vertical growth phase
What are the four subtypes of melanoma?
Lentigomaligno melanoma (junction)
Superficial spreading
Nodular (early vertical growth phase, poor prognosis)
Acral lentiginous (arises on palms or soles, often in dark-skinned individuals; not related to UV light exposure)
Superficial bacterial skin infection usually Staph aureus or strep progenies
Impetigo
Tender rash with fever
Cellulitis
Necrosis of subcutaneous tissue due to infection with anaerobic bacteria; production of CO2 leads to crepitus
Necrotizing fasciitis
Sloughing of skin with erythematous rash and fever?
Staph aureas infxn –> exfoliative A and B toxins –> separation of at layer of stratum granulosum
Staph scalded skin
Mechanism of
Exfoliative A and B toxins result in epidermolysis of stratum granulosum
TEN = ?
Toxic epidermal necrolysis; separation at dermal-epidermal junction
flesh-colored papule with rough surface due to HPV
Verruca
Firm, pink umbilicated papule due to poxvirus; most often arises in children; also in sexually active or immunocompromised adults
Molluscum contagiosum
Histological finding in molloscum contagiosum?
mollosucum bodies within keratinocytes
From what embryonic structure are melanocytes derived?
Neural crest
At what level in the epidermis are melanocytes found?
Basal
Melanocytes synthesize melanin from WHAT?
tyrosine
Autoimmune destruction of melanocytes –> localized loss of skin pigmentation
vitiligo
Patient goes to tan and certain areas don’t become dark?
Vitiligo
Benign squamous proliferation; often in elderly; classic “stuck on” appearance
Seborrheic Keratosis
Histologic presentation of SK
Pseudocytes (circular spaces with abundant pink collagen)
Sudden onset of multiple SKs
suggests underlying GI carcinoma - Leser -Trelat sign
Epidermal hyperplasia with darkening of skin that feels like velvet (usually groin or axilla0
associated with insulin resistance or malignancy
Malignant proliferation of basal cells; risk factors all based on UVB exposure (sun exposure; albinism; xeroderma pigmentosum (autosomal recessive defect in enzymes related to nucleotide excision repair pathway))
Basal cell carcinoma
Elevated nodule with central area of necrosis and telangectasias; arises on upper lip
basal cell carcinoma
peripheral palisading
basal cell carcinoma
Ulcerated, nodular mass on lower lip
Squamous cell carcinoma
Risk factors for SCC
immunosuppressive therapy; arsenic poisoning chronic inflammation (e.g. scar from burn or draining sinus tract); UVB light
Precursor to SCC; presents as a hyperkeratotic, scaly plaque on face, back, or neck
Actinic Keratosis
Well-differentiated SCC; develops rapidly and regresses spontaneously
Keratoacanthoma
Cup shaped tumor filled with keratin debris
Keratoacanthoma
Autoimmune destruction of desmosomes due to IgG antibody against desmoglein
Pemphigous vulgaris
