lichen planus

[plānəs]
n.
  1. A skin condition characterized by the eruption of flat-topped, shiny, violaceous papules on flexor surfaces, male genitalia, and the mucosa of the oral cavity.lichen ruber planus
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.