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Degeneration occurs in response to... (4)
physical damage, infection, inflammation, or metabolic disorders.
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Proliferative responses always indicate ___________.
chronic disease
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What is hyperkeratosis?
increased thickness of the stratum corneum, in which the cells have no nuclei
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Hyperkeratosis is aka __________.
orthokeratotic hyperkeratosis
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What is parakeratosis?
increased thickness of the stratum corneum with retention of nuclei
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Parakeratosis is aka _____________.
parakeratotoic hyperkeratosis
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Hyperkeratosis and parakeratosis are common features of ____________, producing the clinical manifestations of... (4)
chronic dermatoses; scale, crusts, scabs, and lichenification.
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What dermatological manifestation arises from Vit A or Zinc deficiencies?
diffuse perakeratosis
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What is acanthosis? (2)
increased thickness of the stratum spinosum, hyperplasia of the epidermis
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How do rete ridges form?
acanthosis--> path of least resistance is down--> hyperplastic epidermis forms downward projections that extend into the dermis but are still attached to the epidermis (not invading dermis)
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The "wavy border" b/w the epidermis and dermis that is caused by acanthosis/rete ridges.
psoriasiform (psoriasis) hyperplasia
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When does pesudoepitheliomatous hyperplasia occur?
when hyperplasia and acanthosis become extreme due to intense chronic irritation, causing rete ridges to become very long and form cross-bridges
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What is epidermal atrophy associated with?
metabolic disorders/endocrine dermatoses
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Abnormal growth of keratinocytes in which the cells lose normal relationship b/w one another, forming atypical growth patterns is called ____________ and is usually found in association with ____________.
epidermal dysplasia; neoplasms or preneoplastic syndrome
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Apoptosis (premature death or accelerated keratinization) was previously known as __________ and is a feature of __(2)__.
dyskeratosis; metabolic disorders or immune-mediated diseases.
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What is a Civatte body?
a degenerate or apoptotic keratinocyte confined to the stratum basale
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What are Civatte bodies associated with?
feature of lichenoid or interface dermatitis
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Describe hydropic degeneration.
swollen cells with expanded cytoplasm and clear vacuoles or perinuclear space
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Hydropic degeneration represents ____________.
intracellular edema
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What is edema associated with?
pathologic processes promoting vascular leakage or damage (such as inflammation, vasculitis)
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What is koilocytosis?
type of hydropic degeneration in which the cell cytoplasm is swollen but does not contain a discrete vacuole- indicative of viral infection
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Describe spongiosis.
separation or pulling apart of keratinocytes with clear spaces b/w them caused by intercellular edema
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The migration of inflammatory cells into and through the epidermis, contributing to scab and crust formation.
exocytosis
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How do vesicles and clefts form?
if spongiosis becomes severe enough, creating a fluid filled cavity or pocket in or beneath the epidermis [clefts are vesicles beneath the epidermis]
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What are pustules?
vesicles filled with inflammatory cells or degenerate keratinocytes
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What is acantholysis?
loss of cohesion b/w keratinocytes due to degeneration of the intercellular cement and desmosomes, resulting in the formation of intraepidermal clefts and pustules
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Describe what acantholytic cells look like on histology.
keratinocytes that lose their polygonal shape and become rounded spheres floating in the edema fluid
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What are potential causes of melanosis/hyperpigmentation? (3)
increased melanin synthesis, increased transfer of melanin to keratinocytes, decrease in melanin degradation
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Focal spots of hypopigmentation.
vitiligo
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What is the pathology of furunculosis?
keratin leaks into the dermis, which stimulates an intense and irritating inflammatory response
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What is pigmentary incontinence associated with?
interface dermatitis--> discoid lupus
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What does mucinous degeneration of dermal collagen look like on histopathology?
amorphous, stringy to granular basophilic material that separates the collagen bundles
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How does calcinosis cutis occur?
mineralization of dermal collagen fibers during degeneration- Cushing's disease
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Collagen fiber degeneration associated with eosinophils, which occurs b/c eosinophils contain major basic protein, which mediates degeneration- as seen on histopathology.
"flame figures"
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An inappropriate increase in the amount of dermal collagen may be called... (3)
fibrosis, sclerosis, or fibroplasia.
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When dermal proliferation is stimulated by fibroblast growth factors secreted by neoplastic cells, it is termed _____(2)_____.
desmoplasia or reactive fibrosis
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Fibroblastic connective tissue that is rich in sprouting capillaries.
granulation tissue
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What is a unique characteristic of granulation tissue on histopathology?
capillaries are oriented perpendicular to the fibroblasts and collagen bundles
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An abnormal decrease in the amount of dermal collagen, often with collagen looking normal on histo but only thinner.
atrophy
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Dermal atrophy is a feature of __________.
metabolic/endocrine disorders
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How does dermal dysplasia appear on histopathology?
disorganization of poorly defined collagen bundles
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What does vasculitis look like histologically?
numerous neutrophils within the capillary wall and migrating out of the capillary into the dermis
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When does pigmentary incontinence occur?
when basal epithelium is damaged and cells cannot hold melanin granules, causing them to "leak" into the superficial dermis, where they are phagocytized by macrophages
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Severe damage to follicles results in loss of the hair is seen clinically as __________.
alopecia
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What characterizes telogen phase hairs?
"club hairs"- have a jagged zone of keratin near the base b/c they are separating from the outer root sheath--> alopecia
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Common causes of folliculitis. (3)
mites (Demodex), dermatophytes (ringworm), bacteria (Staph)
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Hypertrophy and hyperplasia of sebaceous glands is usually secondary to __________.
chronic dermatitis
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Hypoplasia and atrophy of sebaceous glands is usually a sign of ___________.
metabolic/endocrine disorders
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Describe the histological appearance of superficial perivascular dermatitis.
acute inflammatory cells accumulate around superficial and mid-ermal vessels, often with dermal edema
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What are some causes of superficial perivascular dermatitis? (3)
hypersensitivities, ectoparasites, infections
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Describe the histological appearance of interface/lichenoid dermatitis.
form of superficial perivascular dermatitis in which the inflammation is concentrated right at the dermal-epidermal junction
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What causes interface/lichenoid dermatitis?
autoimmune diseases
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What causes periadnexal/nodular dermatitis?
bacterial, fungal, or parasitic infections of the hair follicles/adnexal structures
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What is ulcerative dermatitis, and what usually causes it?
epithelium is removed, usually by self-inflicted trauma, usually secondary to pruritic skin disorders
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What is vesicular or pustular dermatitis?
vesicles or pustules form at different layers of the epidermis- symmetrical distribution on the body
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What manifests as vesicular or pustular dermatitis?
immune-mediated skin disorders, such a pemphigus
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Describe the histological appearance of endocrine dermatosis.
characterized by atrophy of the epidermis, follicles, adnexae, and sometimes a thin dermis
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