Sebaceous cyst is a benign skin condition in which sebum accumulates and forms cysts. Sebaceous glands are the glands responsible for the secretion of oil to moisturize the skin and are distributed all over the body. If the hair follicles are blocked by secretions or narrowed after injury, the sebaceous glands are obstructed in their excretion and the sebaceous glands continue to secrete and the secretions continue to increase, the cysts will gather and thus form sebaceous cysts. Sebaceous cysts are found on the head, face, back, buttocks and other parts of the body. They are usually present in the skin, round in shape, smooth on the surface, moderately hard or elastic, and may become pus-filled, red, swollen, and painful when a bacterial infection develops. Sebaceous cysts are slow-growing and generally do not require treatment. However, if there is a sudden increase in the size of the cyst, which presses on the surrounding tissues and leads to discomfort, it is recommended to go to the dermatology department of the hospital for consultation and treatment.