achromia

[ā-krōmē-ə, ə-krō-]
n.
  1. Congenital or acquired deficiency of natural pigmentation.
  2. Lack of capacity to accept stains in cells or tissue.achromasia achromatosis
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.