Pathology > Skin > Flashcards
Skin Flashcards
bulla
elevated fluid filled lesion more than 5 mm
excoriation
linear, traumatic epidermal disruption
lichenification
thick, rough skin with prominent skin markings, usually due to repeated rubbing
macule
flat circumscribed area 5 mm or more distinguished by coloration
onycholysis
separation of nail from underlying skin
nodule
elevated dome-shaped lesion more than 5 mm
papule
elevated lesion 5 mm or more
plaque
elevated flat-topped lesion more than 5 mm
pustule
discrete, pus-filled raised lesion
scale
dry, plate-like excrescence due to aberrant cornification
vesicle
elevated fluid-filled lesion 5 mm or more
wheal
pruritic, elevated, erythematous lesion secondary to dermal edema
acantholysis
loss of intracellular keratinocyte connections
acanthosis
epidermal hyperplasia
dyskeratosis
abnormal keratinization below the stratum granulosum
erosion
focal incomplete epidermal loss
exocytosis
epidermal inflammatory cells
hydropic swelling
intracellular keratinocyte edema
hypergranulosis
stratum granulosum hyperplasia, rubbing
hyperkeratosis
stratum corneum thickening often with aberrant keratinization
lentiginous
linear melanocyte proliferation within the epidermal basal cell layer
papillomatosis
surface elevation due to dermal papillae hyperplasia
parakeratosis
stratum coreneum keratinization with retained nuclei
spongiosis
epidermal intracellular edema
ulceration
focal, complete epidermal loss
vacuolization
vacuoles within or adjacent to keratinocytes
Freckles (ephelis)
pigmented lesions of childhood, 1-10mm tan-red to brown macules
Morph: melanocyte density normal, hyperpigmentation result of focal melanin over-production and/or enhanced pigment donation to basal keratinocytes
Lentigo
Benign hyperpigmented macule common in infancy and childhood
- no change with sun exposure
Morph: hyperpigmented linear basal melanocyte hyperplasia often with rete ridge elongation and thinning
Melanocytic Nevus, pigmented nevus, mole
Congenital or acquired melanocyte neoplasms, well demarcated, uniformly tan-brown papules
Morph: basal melanocytes derived
- junctional nevi - nests of nevus cells at dermoepidermal junction
- compound nevi - nests or cords of melanocytes extending into dermis
- dermal nevi - epidermal component is lost
–> maturation
Path: BRAF or NRAS involved in RAS signaling to p16/INK4a
Dysplastic nevi
Larger than most acquired
- flat macules to raised plaques with variegated pigmentation and irregular borders in both sunexposed and protected skin
- low risk of malignant transformation
Morph: compound nevi with cytologic and architectural atypia
- enlarged and fused nests of nevus cells, lentiginous melanocyte hyperplasia, linear papillary dermal fibrosis
Path: auto dom disorder often associated with mutations in protein with cell cycling
Melanoma
Skin, oral, anal surfaces, esophagus, meninges, eyes
Clinical sx: changes in size, shape, or color of cutaneous skin, can be irregular or notched
Morph: large cells with expanded irregular nuclei containing peripherally clumped chromatin and eosinophilic nucleoli
- radial growth
–> lentigo maligna, indolent lesion that may not progress for decades
–> superficial spreading, most common form involving sun exposed skin
–> acral/mucosal lentiginous, melanoma unrelated to sun exposure
- vertical growth
–> dermal invasion of clonal mass of cells, can metastasize
Diagnostic factors: breslow thickness, mitosis, regression, tumor-infiltrating lymph, gender, location, micrometastasis
Path: sun exposure, familial inheritance or genes
- dysplastic nevus syndrome, RAS and PI3K/AKT, BRAF, RB
Seborrheic keratoses
Age: middle to older individuals
Path: leser-trelat - paraneoplastic syndrome due to TGF alpha and FGFR
Morph: Grossly - uniform, tan-brown, velvety or granular plaques
Micro - sharply demarcated and exophytic with hyperplasia of variably pigmented basaloid cells and hyperkeratosis, horn cysts
acanthosis nigricans
thickened, velvety hyperpigmented plaques in flexural areas
- benign or malignant conditions
–> benign is 80% and arises through puberty, auto dom
–> malignant type in middle and older indiv with adenocarcinomas
Morph: hyperkeratosis with rete ridges and basal hyperpigmentation
fibroepithelial polyp
acrochordon, squamous papilloma or skin tag
- found on face, neck, trunk or intertriginous zones
Morph: soft flesh colored tumors attached by slender fibrovascular stalk
Assoc: pregnancy, diabetes, intestinal polyposis
epithelial cyst (wen)
Common lesions as well-circumscribed firm subcutaneous nodules formed by downgrowth and cystic expansion of epidermal or follicular epithelium
Morph: filled with keratin and lipid and debris from sebaceous secretions
- epidermal inclusion cyst –> wall identical to normal epidermis
- pilar (trichilemmal) cyst –> wall follicular epithelium
- dermoid cyst –> wall similar to epidermis but has multiple skin appendages
- steatocystoma multiplex –> wall resembles sebaceous gland ductal epithelium
Adnexal tumors
Nondescript, flesh-colored benign papules or nodules
- subset can be malignant
- cowden syndrome for visceral malignancies in tumor suppressor gene PTEN
- -> cylindromas - scalp and forehead, islands of basaloid cells with apocrine or eccrine differerntation
- -> syringomas - mutliple, small, tan papules near lower eyelids and are composed of basaloid epithelium
- -> sebaceous adenomas - lobular proliferations of sebocytes with frothy lipid filled cytoplasm
- -> trichoepitheliomas - proliferations of basaloid cells that form hair follicle-like structures
- -> pilomatrixomas - proliferations of basaloid cells that show hair-like differentatiation
- -> apocrine carcinomas - axilla and scalp with ductal differentation
actinic keratosis
premalignant dysplastic lesion with chronic sun exposure
Morph: grossly - lesions 1 cm, tan-brown, red, flesh colored
micro - cytologic atypia in lower epidermis frequently with basal cell hyperplasia and dyskeratosis
–> hyperkeratosis and parakeratosis exhibit thickened, blue-gray elastic fibers
squamous cell carcinoma
Second most common tumor of sun-exposed skin of older individuals
Gender: men more than women
Morph: grossly - in situ sq cell carcinomas well demarcated, red, scaling plaques; invasive lesions are nodular
micro - in situ carcinoma full thickness epidermal atypia; invasive tumors vary from well differentated to highly anaplastic with necrosis
- keratoacanthoma - spontaneously resolving rapid growing lesion
grossly - lesions are symmetric, cupshaped nodules
micro- lobules of glass squamous cells keratinize progressing through a granular layer
Path: UV radiation is greatest predisposing factor by inducing DNA damage by dampening immune functioning of langerhans cells
Risks: industrial carcinogens, chronic skin ulcers, old burn scars, osteomyelitis, ionizing radiation, tobacco
- p53 mutations
basal cell carcinoma
Most common invasive human cancer
- slow growing and rarely metastasize
- immunosuppression and defects in DNA repair
Morph:
- grossly, pearly papules often with prominent telangiectatic vessels
- micro, monotonous basal cell proliferation multifocal superficial growths of skin or as nodules
Path: nevoid basal cell carcinoma syndrome
- -> rare auto dom disorder by multiple basal cell CA
- medulloblastomas, ovarian fibromas, odontogenic keratocysts
- PTCH, SHH
Dermatofibroma (benign fibrous histiocytoma)
Heterogenous group of indolent neoplasms of dermal fibroblasts and histiocytes in adults
- legs of young women
- trauma and aberrant healing
Morph: grossly - lesions firm tan-brown tender papules
micro - dermatofibromas most common, spindle-shaped fibroblasts is a well-defined mid-dermal mass
Dermatofibrosarcoma protuberans
Well-diffrentiated slow growing fibrosarcoma locally aggressive but rarely metastasizes
Morph: tumors are firm nodules as protuberant and ulcerated aggregates within an indurated plaque
micro - lesions are cellular and composed of radially oriented fibroblasts
Path: balanced transolcation between collagen 1A1 and PDGFbeta
Mycosis fungoides (cutaneous T cell lymphoma)
Cutaneous T cell lymphoma, mycosis fungoides d’emblee more aggressive
- can involve into generalized lymphoma
- with erythroderma with sezary syndrome
Morph: grossly - eczema and arise on trunk, progress to scaly, red-brown patches, scaling plaques or fungating nodules
Micro - sezary lutzner cell, malignant CD4+ cell with hyperconvoluted or cerebriform nucleus
Mastocytosis
Rare disorders characterized by increased numbers of cutaneous mast cells
Sx: consequences of mast cell degranulation, histamine release causes pruritus, flushing, rhinorrhea, dermal edema and erythema
Morph: grossly - skin lesions multiple, round-oval, nonscaling redbrown papules and plaques
micro - dermal fibrosis, edema, eosinophils
ichthyosis
Disorders of epidermal maturation leading to chronic excessive keratin accumulation resembling fish scales
x-linked autosomal recessive and auto dom forms, acquired variants can be associated with various malignancies
Morph: micro - lesions exhibit stratum corneum with minimal inflammation, thickness of epidermis or stratum granulosum
urticaria
focal mast cell degranulation with histamine mediated dermal edema and pruritus
- angioedema has dermal and subcutaneous fat
Morph: grossly - small, pruritic papules to large edematous plaques
micro - sparse mononuclear perivascular infiltrates
Path: IgE independent urticaria can occur through chemical induced mast cell degranulation or by suppression of prostaglandin synthesis
Acute eczematous dermatitis
Types:
- allergic contact dermatitis, atopic dermatitis, drug-related eczematous dermatitis, photoeczematous dermatitis, primary irritant dermatitis
Morph: grossly - pruritic, red, and papulovesicular to blistered, oozing, and crusted –> can go to psoriasis
micro - early spongiosis progresses to frank fluid accumulation, splaying keratinocytes apart and forming intraepidermal vesicles
Path: eczema constitute a cutaneous delayed type hypersensitivity response driven by langerhands cell presentation of antigens acquired at the epidermal surface
Erythema multiforme
Uncommon self-limited hypersensitivity response triggered to drugs, infections, malignancy, or collagen vascular disorders
Stevens-johnson syndrome - severe febrile form occurring in children, erosions and hemorrhagic crusting of the lips, oral mucosa, conjunctiva, urethra, anogenital regions
toxic epidermal necrolysis - variant, characterized by diffuse mucocutaneous epithelial necrosis and sloughing
Morph: grossly - multiform lesions include macules papules, vesicles and bullae
micro - dermal-epidermal and perivascular lymph infiltrates with dermal edema and focal basal keratinocyte degeneration and necrosis
Path: immunologic cutaneous disorders, epi cells injured by skin-homing CD8+ cytotoxic T lymph
Psoriasis
1-2% of population
Assoc: arthritis, myopathy, enteropathy, spondylitic join disease, AIDS
Areas: elbows, knees, scalp, lumbosacral region, intergluteal cleft, glans penis, nail changes
Morph: grossly - well demarcated, salmon pink plaques with silvery scaling, annular linear gyrate or serpiginous
micro - marked acanthosis with downward rete elongation and with mitosis well above basal layer
–> stratum granulosum is thinned or absent with overlying parakeratosis
–> auspitz sign, spongiform pustules or munro microabscesses
Path: HLA types at Koebner phenomenon
seborrheic dermatitis
seborrhea affects 1-3% of population
Areas: scalp, forehead, nasolabial folds, presternum
Lenier disease - seborrhea, diarrhea, failure to thrive
Morph: grossly - lesions macules or papules on greasy, yellow erythematous base with scaling and crusting
micro - spongiotic dermatitis, later lesions acanthotic psoriasis
Path: lipophilic yeasts may be involved
Lichen planus
self limited disease leaving only postinflammatory hyperpigmentation oral lesions may persist longer
Morph: grossly - pruritic, purple, polygonal planar papules, plaques
–> lesions have wickham striae
micro - dense, bandlike dermal-epidermal junction lymph infiltrate with basal cell degeneration and necrosis and jagged rete sawtoothing
Path: T cell infiltrates with langerhans cell hyperplasia suggest cell-mediated immune injury
pemphigus
autoimmune disorder
Age: 30-60
Tx: immunosuppression to reduce titers of pathogenic autoantibodies
Types:
pemphigus vulgaris - 80% oral mucosa, scalp, face, intertriginous zones, trunk, pressure points
–> superficial easily ruptured blisters with shallow crusted erosions
Pemphigus vegetans - large moist verrucous plaques studded with pustules
pemphigus foliaceus - benign form on face, scalp, upper trunk, bullae superficial
pemphigus erythematosus - localized milder variant of pemphigus foliaceus, malar
paraneoplastic pemphigus - non hodgkin lymphoma
Morph: micro - acantholysis with intercellular clefting and intraepi blisters with variable inflammatory infiltrate
–> above basal layer (suprabasal blister) leaving an intact tombstone like layer
Path: IgG against desmoglein components
Bullous pemphigoid
Autoimmune blistering disease of skin and mucosa affecting elderly individuals
- bullae do not rupture as easily as in pemphigus and if uninfected heal without scarring
Morph: grossly - lesions are 2-8 cm tense bullae containing clear fluid
–> thigh, forearm flexor surfaces, lower abdomen, intertriginous zones, oral mucosa
micro - subepidermal non-acantholytic blister with linear dermoepidermal juntion
path: autantibodies against hemidesmosome
dermatitis herpetiformis
Pruritic urticaria and grouped vesicles associated with celiac disease and responds to gluten-free diet
Path: immune complex deposition in skin or gliadin antibodies cross-reacting with junction-anchoring components
Morph: grossly - plaques and grouped vesicles bilateral and symmetric involving extensor surfaces, upper back, buttocks
micro - neutrophils and fibrin accumulate at tips of dermal papillae with overlying basal vacuolization coalescing to large subepidermal blisters
acne vulgaris
common chronic lesion of hair follicles sebaceous glands
Age: middle to late adolescence
Gender: males more than female
Assoc: hormonal changes and alterations in hair follicle maturation
Morph: grossly - noninflammatory acne by open comedones and closed comedones, inflammatory acne with erythematous papules, nodules, pustules
micro - comedones composed of expanding masses of lipid and keratin at midportion of hair follicles
Path: bacterial (propionibacterium acnes) lipase degradation of sebaceous oils to form highly irritating fatty acids and incite the early inflammatory lesions
rosacea
3% of US pop with a predilection for middle aged women
Morph: grossly - flushing, erythema and telangiectasia, pustules and papules, rhinophyma
micro - nonspecific perifollicular lymphocyte infiltrate with dermal edema and telangiectasia
Path: innate immune system with inappropriate activation
erythema nodosum
Most common form of panniculitis
- associated with drugs, infections, sarcoidosis, IBD, visceral malignancy
Sx: ill-defined tender erythematous nodules with fever and malaise
erythema induratum
uncommon panniculitis affecting adolescents and menopausal women
- primary vasculitis of subcutaneous fat with inflammation and necrosis
Sx: erythematous tender nodule that ulcerates and scars
weber-christian disease - febrile nodular panniculitis rare lobular form of panniculitis with erythematous plaques or nodules
verrucae (warts)
Caused by HPV
- verruca vulgaris, most common typically found on hand dorsum
- verruca plana, hand or face as flat, smooth, tan papules smaller than verruca vulgaris
- verruca plantaris or palmaris, rough scaly that can coalesce and be confused with calluses
- condyloma acuminatum, soft tan cauliflower like masses measuring up to many centimeters in diameter
Morph: micro - epidermal hyperplasia and superficial keratinocyte perinuclear vacuolization koilocytosis
Path: HPV 6,11,16
Molluscum contagiosum
Poxvirus infection
Morph: grossly - firm, pruritic, pink to skin-colored, umbilicated papules
micro - cuplike verrucous epidermal hyperplasia with pathognomonic molluscum bodies
impetigo
staph aureus and strep
- highly contagious involves face and hands
- bullous in children
Morph: grossly - erythematous macules that progress to small pustures with honey colored crust
micro - subcorneal pustules filled with neutrophils and gram pos cocci
Path: epidermal bacterial infections with destructive innate immune repsonse
