S4C24P16Amyloidosis


S4C24P16-1: The epidermis shows hyperkeratosis, a prominent granular layer, hyperplasia of both the superficial and basal units of the epidermis, and regular elongation of rete ridges. Dermal papillae are elongated and broad. They show an increased number of blood vessels. The vascular changes, in large part, are an expression of angiodermatitis, as commonly expressed in association with inflammatory processes on the lower extremity. Focally, at the tips of the dermal papillae, the basal layer of the epidermis is poorly defined. The widened papillary dermis appears somewhat hyalinized at this magnification ( lichen amyloidosis).


S4C24P16-2: At higher magnification, there are globular, acidophilic bodies at the dermal-epidermal interface and in the broad dermal papillae (red arrows). The dermis is relatively free of lymphoid infiltrates (lichen amyloidosis).

S4C24P16-3: Pale acidophilic, globular deposits (amyloid) are prominent in the papillary dermis. The mononuclear cells, by their nuclear characteristics, probably are histiocytes (lichen amyloidosis).

S4C24P16-4: Amyloid has metachromatic qualities with this congo red stain. The amyloid is more intensely reddish-orange than either the dermal connective tissue, or the epidermis. The deposits characteristically press upon the overlying epidermis and, presumbably, are a product of keratinocytes.

S4C24P16-5: This is the pattern of a positive congo red stain in macular amyloidosis. In the region of the red arrows, the basal layer is interrupted. It is in this manner that the process histiologically has lichenoid qualities.

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