Cysts - epidermoid and pilar
By definition, cyst is a closed sac that has 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 white toothpaste. This is made of keratin - the material that makes up hair and the outer layer of the skin.
In the past, pilar and epidermoid cysts were wrongly known as ‘sebaceous’ cysts but this term should be used only for a quite different and much less common type of cyst that is filled with a clear oily liquid made by sebaceous (grease) glands.
Epidermoid and pilar cysts are common, not cancerous, and not contagious.