keratoacanthoma

[kĕr′ə-tō-ăk′ən-thōmə]
n.
  1. A rapidly growing skin tumor having a central keratin mass and usually occurring on exposed areas, invading the dermis but remaining localized and usually healing spontaneously.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.