Cysts - Epidermoid and Sebaceous  - Introduction

Introduction Causes Symptoms Treatments

By definition, cysts are closed sacs that have two main features:
  • A lining.
  • Contents that are liquid or semi-solid. 

The lining

Differences between the lining of epidermoid and pilar cysts can be seen under the microscope:

  • The lining of an epidermoid cyst looks like the epidermis (the outermost layer of cells in the skin).
  • The lining of a pilar cyst is made up of cells like those found in the roots of hairs.

The contents

Both types of cyst contain a cheesy material, looking rather like toothpaste.  This is made of soggy keratin - the material that makes up hair and the outer layer of the skin.