dermoid cyst

n.
  1. A benign tumor resulting from abnormal embryonic development, occurring in the skin or ovary, and consisting of displaced ectodermal structures along the lines of embryonic fusion.dermoid dermoid tumor
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.