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Skin-nontumor / Clinical Dermatology


Common Pathologic Terms

Reviewer: Cecilia Rosales, M.D, Baylor College (see Reviewers page)
Revised: 24 August 2011, last major update August 2010
Copyright: (c) 2002-2011, PathologyOutlines.com, Inc.


Acantholysis: loss of intercellular connections (desmosomes) between keratinocytes; occurs in pemphigus vulgaris and related disorders; causes change in cell shape from polygonal to round
Acanthosis: thickening of epidermis (squamous layer); rete ridges usually extend deeper into dermis
Atrophy: thinning of epidermis, associated with age or disease
Basophilic degeneration: age and sunlight related changes of collagen and elastic fibers
Blister: vesicle or bullae
Bullae: fluid filled area > 5 mm; either intraepidermal or subepidermal; intraepidermal bullae are due to spongiosis or acantholysis; subepidermal bullae are due to extensive papillary dermal edema
Calcinosis: deposit of calcium
Colloid bodies: also called Civatte bodies; apoptotic keratinocytes, are oval/round, immediately above or below epidermal basement membrane
Comedo: hair follicle infundibulum is dilated and plugged with keratin and lipids
Cyst: encapsulated cavity or sac lined by true epithelium
Dyskeratosis: abnormal, premature keratinization of keratinocytes below granular cell layer; often have brightly eosinophilic cytoplasm
Epidermolysis: alteration of granular layer with perinuclear clear spaces, swollen and irregular keratohyalin granules, increased thickness of granular layer; different from acantholysis
Epidermotropism: atypical lymphocytes present in epidermis (seen in cutaneous T cell lymphoma)
Erosion: discontinuity of skin causing partial loss of epidermis (compare to ulceration)
Excoriation: deep linear scratch, often self-induced
Exocytosis: normal appearing lymphocytes in epidermis (spongiotic dermatitis)
Horn: conical mass of cornifed cells
Hydropic (liquefactive) degeneration: basal cells become vacuolated, separated and disorganized
Hyperkeratosis: thickened cornified layer, often with prominent granular layer; keratin may be abnormal; either orthokeratotic (hyperkeratosis is exaggeration of normal pattern of keratinization with no nuclei in cornified layer) or parakeratotic (hyperkeratosis has retained nuclei in cornified layer)
Lentiginous: linear pattern of melanocytic proliferation within epidermal basal cell layer
Leukocytoclasis: karyorrhexis and destruction of neutrophils; occurs with neutrophilic vasculitis (also called leukocytoclastic vasculitis)
Lichenification: thick, rough skin with prominent skin markings usually due to repeated rubbing
Lichenoid interface change: destruction of basal keratinocytes, causing remodeling of basement membrane zone; also bandlike lymphocytic infiltrate
Macule: circumscribed flat colored area of any size
Nodule: solid, deeply extending lesion > 5 mm
Oncholysis: loss of integrity of nail substance
Papillomatosis: outward overgrowth of epidermis with elongation of dermal papillae
Papule: elevated and solid area, 5 mm or less
Parakeratosis: cells of cornified layer retain their nuclei, often less prominent or absent granular layer; normal for mucous membranes
Patch: flat discoloration > 5 mm
Papule: solid elevated lesion < 5 mm
Plaque: elevated flat topped area, usually > 5 mm
Poikiloderma: combination of atrophy, telangiectasia and pigmentary changes
Purpura: extravasation of red blood cells into the skin or mucous membranes
Pustule: intraepidermal or subepidermal vesicle or bullae filled with neutrophils
Scale: dry, horny, platelike excrescence usually due to imperfect cornification
Scale crust: parakeratotic debris, degenerating inflammatory cells and tissue exudate on surface of epidermis
Sinus: tract connecting cavities to each other or to the surface
Spongiosis: intraepidermal edema, causing splaying apart of keratinocytes in stratum spinosum (resembling a sponge), vesicles due to shearing of desmosomes
Ulceration: discontinuity of skin causing complete loss of epidermis and possible loss of dermis
Vesicle: fluid filed area, 5 mm or less
Wheal: itchy, transient, elevated area with variable blanching and erythema, due to dermal edema

End of Skin-nontumor / Clinical Dermatology > General > Common Pathologic Terms

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