It is also called epidermoid cysts. Cysts are non-cancerous closed pockets of tissue that can be filled with fluid, pus, or other material. It is a benign skin cyst formed from blocked sebaceous glands in the skin. Apart from the face, it is most commonly found on the trunk, back, and scalp.

A little black opening of the cyst is visible on the skin. If it is infected, it will become red and tender. When it is squeezed, a cheesy white paste material is discharged, sometimes can be quite smelly.

To remove it effectively, the whole sac of the cyst must be completely removed. If the cyst is squeezed to force out the discharge, or if part of the sac wall is left behind, the cyst will reappear later.