derm Flashcards
xanthoma
associated with hyperlipidemia or lymphoproliferative malignancies; associated with lipid-laden histiocytes in the dermis
cherry/senile hemangioma
small, bright-red papular lesions in 3rd/4th decade; do not regress spontaneously and are always cutaneous
strawberry hemangioma
appear in infants; regress spontaneously by 5-8 years of age; bright red near epidermis, more violaceous if deeper
cavernous hemangiomas
dilated vascular spaces with thin-walled endothelial cells in the dermis; appear on skin, mucosa, viscera; if on brain/viscera, consider VHL
cystic hygromas
lymphatic cysts lined by a thin endothelium; present at birth along neck and lateral chest wall; found in turner/t21 syndrome
xerderma pigmentosum
AR mutation that impaires DNA excision repair following UV dmg; pw erythema, scaling, and subsequent hyperpigmentation and lentigo formation in light-exposed areas; skin malignancies develop at 5-6 years of life
fanconi anemia
AR, hypersensitivity to DNA cross-linking agents
male patten baldness pw, moa, rx
anterior/vertex balding; scalp 5-alpha reducetase activity and the androgenic effects of DHT; finasteride
PKU pw, genetics
mental retardation, eczema, mousy body order; AR mutation of phenylalanine hydroxylase
PABA-ester sun screen
UVB radiation (290-320) absorbers
acanthosis
increase in thickness of stratum spinosum (seen in psoriasis)
dyskeratosis
abnormal, premature keratinization of keratinocytes; strongly eosinophilic (seen in SCC)
hyperparakeratosis
retention of nuclei in the stratum corneum, incomplete keratinization (normal in mucosa, but abnormal in skin - actinic keratosis)
hyergranulosis
excess granulation in the stratum granulosom of the epidermis (seen in lichen planus)
spongiosis
intercellular epidermal edema that appears as an increase in the width of spaces between cells; primary histological finding in pt with eczematous dermatitis
RBC extravasation into skin/subQ tissues results in formation of what?
petechiae (1 cm); do not blanch as capillaries are not patent
thymidine kinase-deficient VCV means? how to treat?
acyclovir-resistent VCV in AIDS pt; rx with foscarnet (pyrophosphate analog viral DNA polymerase inhibitor) or cidofovir (antiviral nucleotide analogue of cytidine monophosphate, does not require viral kinase)
marjolin’s ulcer
aggressive, ulcerating SCC on area of previous trauma, chronically inflammed or scarred skin
isotretinoin moa, SE
inhibits follicular epidermal keratinzation, loosening keratin plugs of comedones; hypertriglyceridemia and teratogenicity
stewart-treves syndrome
chronic lymphedema (2/2 axillar LN dissection) predisposes to angiosarcoma
lichen planus pw (5 Ps)
polygonal, planar, pruritic, purplish plaques; a.w. hep C
xanthelesma pw, histo, a.w.
yellow cutaneous lesion on eyelid; lipid-laden macrophages in superficial dermis; cholestatic processes like obstructive biliary lesions or PBC
vitiligo histo
loss of melanocytes, complete absence of melanin pigment
albinism histo
melanocytes that do not produce melanin (because of absent/defective tyrosinase)
pemphigus vulgaris pw, moa
painful, flaccid bullae and erosions ofskin/mucosal membranes; autoantibodies against desmoglein
chronic steroid administration to skin results in:
atrophy/thinning of dermis, a.w. loss of dermal collagen, dring/cracking/tightening, telangiectasias, ecchymosis
atopic eczematous dermatitis: histo
intraepidermal vesicles, superficial epidermal hyperkeratosis producing scales, epidermal hyperplasia (acanthosis), chronic inflammatory infiltrate
actinic keratosis
erythematous papules with central scale/rought “sandpaper-like” texture; premaligmant (SCC)
acantholysis
loss of intercellular connections
pemphigus vulgaris
acantholysis forming suprabasal blisters, IgG deposits in reticular pattern around keratinocytes
dermatitis herpetiformis: light microscopy
accumulation of PMN on the tips of dermal papillae
HPV: light microscopy
cytoplasmic vacuoles in keratinocytes (koilocytosis) and hyperplasia of the epidermis
molluscum contagiosum
eosinophilic cytoplasmic inclusions in infected cells
androgenetic alopecia inheritance pattern
polygenic with variable penetrance; pattern/severity varies b/w males and females depending on circulating androgen levels
dermatitis herpetiformis pw, moa, histo
herpes-like lesion (erythematous, pruritic papules, vesicles, bullae that appear bilaterally and symmetrically on extensor surfaces); IgA antibodies agianst gliadin (wheat protein) that cross-reacts with reticulin, a protein in the epidermal BM; microabscessess containing fibrin and PMN in dermal papillae tips
leprosy: tuberculoid vs lepromatous
tuberculoid: positive lepromin skin test, strong TH1 cell-mediate response (IL-2, IFN-gamma, IL-12), macrophages kill organisms and lead to smal number of hypopigmented, well-demarcated plques with decreased sensation; lepromatous: negative lepromin test, Th2 response (IL4, IL-5, IL-10), pw more numerous polry demarcated plaques widespread throughout body)
glomus tumor
glomus body: small, encapsulated neurovascular organs surrounded by smooth muscle found in the dermis of the nail beed, pad of finger/toes/ears; role is to shunt/direct blood depending on tempreature to maintain temperature
psoriasis moa, histo
CD4/CD8 T cells activate in epidermis result in production of cytokines (TNF, IL-12, IFN-gamma) and keratinocyte growth factors that stimulate keratinocyte proliferation, inflammation,and angiogenesis; histo: hyperparakeratosis, acanthosis, elogation of the rete ridges, reduced/absent stratum granulosum, thinned epidermal cell layer superior to dermal papilla (pinpoint bleeding= Auspitz sign), PMN form spongiotic clusters in the superficial dermis and parakeratotic stratum corneum
hyperkeratosis
hyperplasia of the stratum corneum
parakeratosis
retained nuclei in the stratum corneum
Does AK invade the dermis?
no; but can evolve into SCC
brain metastasis: most common cancers
lung cancer, renal cancer, and melanoma
apocrine sweat gland causes what lovely finding?
malodorous secondary to bacterial decomposition at the skin surface; present in dermis, subQ fat of breast, axillae, genital regions
eccrine/merocrine glands
present in the skin throughout body, except lips/penis; secrete watery fluid rich in salt
psoriasis rx
topical vitamin D analogs (calcipotriene) that bind to vita D receptor, a nuclear transcription factor that inhibit keratinocyte proliferaiton and stimulate keratinocyte differentiation
melanoma mutation
BRAF is a protein kinase involved in activation of signaling pathway for melanocyte proliferation (BRAF V600E mutation is seen in 40-60% percent of melanoma)
urticaria moa
antigen-induced degranulation of focal mast cells throgh IgE antibody sensitation; OR, IgE-independent urticaria develops after exposure to substances that directly stimulate mast cell degranulation (opiates, antibiotics, contrast)
breast cancer: skin retraction moa
cancer infiltrates suspensory cooper ligaments
