Lichen Amyloidosis Workup

Updated: Dec 09, 2020
  • Author: Sultan Al-Khenaizan, MBBS, FRCPC; Chief Editor: William D James, MD  more...
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Histologic Findings

The diagnosis can usually be made clinically, particularly in patients with the classic presentation. A skin biopsy should be reserved for evolving lesions. Many stains can demonstrate amyloid deposits in the skin. The best known is the Congo-red stain, which under polarizing light gives apple-green birefringence. Other stains include periodic acid-Schiff (PAS); methyl violet; crystal violet; various cotton dyes (eg, pagoda red, Sirius red); and the fluorescent dyes thioflavin-T and Phorwhite BBU.

Amyloid deposits in lichen amyloidosis are found in the papillary dermis, usually at the tips of the dermal papillae. Lichen amyloidosis is distinguished from macular amyloidosis by the presence of marked epidermal changes, including hyperkeratosis and acanthosis.