Skin Pathology (JR)

zoyogasa's version from 2016-04-14 04:42



Question Answer
LayersCome lets get some bitches
Corneum (Keratin)
Spinosum (Desmosomes)
Basale (Melanocytes + Hemidesmosomes)
GlandsSebaceous Gland = holocrine sebum (oil).
Eccrine Gland = sweat (eccrine is everywhere).
Apocrine = milky, thick fluid (from axiallae, genitalia and areolae --> smells bad)
JunctionsTight Junctions = water seals, claudins and occludins
Adherens = connect actin filaments, CADHERINS (E-cadherin loss = metastasis)
Desmosomes = connect keratin
Gap Junctions = connexons = electrical & chemical communication b/w cells
Hemidesmosomes = keratin to basement membrane
Integrins = integrity of BM (laminin)

Flat lesionMacule (<5 mm), Patch (>5mm)
Raised lesionPapule (<5 mm), Plaque (>5 mm)
Fluid, blisterVesicle (<5 mm), Bullae (>5 mm)

Pus filled blisterPustule
Smooth papular or plaqueWheal (hives)
Flaking off of corneumScale (Psoriasis)
Dry exudateCrust (Impetigo)
↑ thickness of corneumHyperkeratosis
↑ thickness of corneum + nucleiParakeratosis
Epidermal hyperplasia (spinosum)Acanthosis

Separation of epidermisAcantholysis ( pemphigus vulgaris)

Albinism↓ tyrosinase. normal # of melanocytes, but ↓melanin/melanosome
Vitiligo↓# of melanocytes
Frecklesnormal # of melanocytes, but ↑melanin/melanosome
Melasma↑melanin during pregnancy/OCP use


Question Answer
Melasmablack mask of pregnancy, line nigra (on stomach)
Melenablack stool (b/c of bleeding in small intestine --> break down of RBC --> oxidation of IRON in hemoglobin) vs. Hematochezia ((blood-deficate) = bleeding in lower GI tract (sigmoid colon or rectum --> bright red blood)
Mesnagive w/ Cycophosphamide (DNA alkylating agent) to ↓ hemorrhagic cystitis (bladder infection)
Melanomamalignant cancer of melanocytes

Inflammatory Dermatosis

Question Answer
Atopic Dermatitis (Eczema)Type I hypersensitivty w/ asthma + allergic rhinitis. Itching, red, oozing rash on Face & Flexors
Contact DermatitisType IV hypersensitivity (Tx = remove irritant)
Acne Vulgariscomeodones (white/blackheads) + pustules (pimples) and nodules. b/c of chronic inflammation of hair follicles and sebaceous glands (trap P. acnes bacteria). (Tx = benzoyl peroxide (kill-bacteria), Vit A(↓ keratin proliferation)
Psoriasissilver scales on Extensor and Scalp, b/c of ↑keratin. HLA-C + trauma. Histo = acanthosis, parakeratosis, munro microabscesses, Auspitz sign = thin epidermis, if pick scale --> beed. (Tx = steroids, PUVA = Psoralen + UVA)
Lichen PlanusP's (Pruritic, planar, polygonal, purple plaque). Wickham stiae = oral. DERMAL-EPIDERMAL junction = saw-tooth. HCV


Question Answer
Pemphigus Vulgarisdesmosomes (spinosum), IgG against desmoglein, Type II, skin + oral, +Nikolsky sign (bullae rupture easily)

Bullae Pemphigoidhemidesmosomes (basale), IgG against hemidesmoglein, Type II, skin ONLY, -Nikolsky sign (bullae do NOT rupture easily)
Dermatitis HerpatiformisCeliac Disease, IgA deposit at Dermal papillae
Erythema MultiformeHypersensitivity, targetoid rash + bullae. HSV infection

Steven-Johnson-SyndromeErythema multiforme + oral/lip involvement + fever (Causes = seizure drugs, sulfonamides, pcn, allopurinol)
Toxin-Epidermal Necrolysis (TEN)SJS w/ >30% body involved

Epithelial Tumors

Question Answer
Seborrheic Keratosis(Sebum + ↑ keratinocytes) benign, raise-discolored plaque on face, stuck-on appearance, Keratin pseudocysts

Leser-Trelat Signsudden onset of multiple seborrheic keratosis --> B/C OF cancer (GI tract)
Acanthosis Nigracanshyperplasia of epidermis + darkening --> axilla or groin. B/c of ~insulin resistance! or GI cancer
Basal Cell Cancer
Upper Lip, malignant, Risk = UVB, albinism, xeroderma pigmentosum, elevated nodule w/ ulcerated crater + telangiectasia, palisading. Tx = excision

Squamous Cell CancerLower Lip, malignant, Risk = UVB, albinism, xeroderma pigmentosum, ~ulcerated, nodular mass on face. Tx = excision

Actinic Keratosisprecursor to SCC, scaly plaque on face, back or neck

Keratoacanthomawell-differentiated SCC, develops fast and regresses fast. cup shaped tumor filled w/ keratin debri



Question Answer
Nevus (mole)benign neoplasm of melanocytes, congenital nevus = has hair. Children = junctional. Adult = compound. Flat macule or raised papule w/ symmetry, sharp borders, evenly distributed color, and <6mm

Melanomamalignant neoplasm of melanocytes, MOLE w/ ABCD = asymmetry, borders irregular, color not uniform, diameter > 6mm. Vertical growth = metastasis. Nodular subtype = metastasis b/c of vertical growth --> poor prognosis
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Infectious Disorders

Question Answer
Impetigohoney-colored crust in children, superficial skin infection, S. aureus or S. pyogenes. very contagious

Cellulitisdeep (dermis + subcutanesou) skin infection from S. aureus or S. pyogenes. Red, tender, swollen rash + fever. Can progress to necrotizing fasciitis w/ necrosis (crepitus) --> medical emergency

Staphylococcal Scalded Skin SyndromeS. pyogenes (Exotoxin A & B) --> sloughing of skin (Stratum granulosum) --> skin loss (TEN (Toxin-Epidermal Necrolysis = at dermal-epidermal junction)

Verruca (wart)HPV infection of keratinocytes, koilocytic change. hands + feet

Molluscum Contagiosummolluscum bodies in keratinocytes, seen in children. poxvirus. firm + pink + umbilicated papules (dimple in the middle)