Epidermoid cysts are small, benign bumps filled with keratin. Kertain is a protein that’s essential in forming your skin, hair, and nails. Epidermoid cysts occur when something blocks hair follicles, and skin cells build up beneath this blockage.

These cysts can look like a skin-colored, tan, or yellowish bump filled with thick material. They typically occurTrusted Source on your face, neck, or torso, but can occur across your body.

In rare cases, epidermoid cysts can be caused by an inherited condition called Gardner syndrome.