What is Sebaceous Cysts ?Sebaceous cysts are small noncancerous lumps or bumps just under the skin. They are closed sacs that contain keratin a protein that often has a foul odor. A sebaceous cyst is also sometimes called an epidermal cyst. It forms when a sebaceous gland, an oil-producing gland in the skin, becomes blocked. This creates a sac that fills with a fatty yellow substance that can resemble cottage cheese.
Although they are usually found on the face, neck, and trunk, they also occur in the vaginal area or other parts of the genitalia. Slow growing these painless cysts rarely cause problems or need treatment.