What Are Sebaceous Cysts?
A sebaceous cyst—sometimes called an epidermal cyst—is a benign (noncancerous) growth in the sebaceous gland (the oil-producing glands under the skin). Sebaceous cysts form because of a ruptured hair follicle, injury or abnormal sebaceous duct. The cysts fill with a protein called keratin, skin particles and lipids (fatty acids).
These cysts are not dangerous and usually don’t require treatment unless they become inflamed or infect.
Sebaceous cysts can develop on anyone of any age, and they tend to run in families.