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Clinical:
most likely a cell-mediated immune response of unknown
origin. An association is noted with hepatitis C virus
infection, chronic active hepatitis, and primary biliary
cirrhosis.
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Location:
most commonly found on the flexor surfaces of the upper
extremities, on the genitalia, and on the mucous membranes.
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Gross:
A pruritic, papular eruption, violaceous
color, shiny, polygonal shape. Varying in size from 1 mm to
greater than 1 cm in diameter. They can be discrete or arranged
in groups of lines or circles. Characteristic fine, white lines,
called Wickham stria, are often found on the papules. Several
clinical presentations: actinic, annular, atrophic, erosive,
follicular, hypertrophic, linear, pigmented, and
vesicular/bullous.
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Histology
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Epidermis:
hyperkeratotic, irregular acanthosis and focal thickening in
the granular layer;
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Lower epidermis:
degenerative keratinocytes, known as colloid or Civatte
bodies;
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Basement membrane
zone: linear or shaggy deposits of fibrin and fibrinogen and
liquefaction;
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Upper dermis: a
band-like infiltrate of lymphocytes and histiocytes with
many Langerhans cells. The infiltrate is very close to the
epidermis and often disrupts the dermal-epidermal junction
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