Sebaceous cysts, commonly known as “pimples,” are cysts that form when sebaceous glands accumulate in the gland due to obstruction of the sebaceous ducts. This is one of the most common benign skin tumors, and many people have had the experience of having a cyst, especially young people in their prime growth spurt. Sebaceous cysts are most common on the scalp and face, followed by the trunk. Because of their varying depths and contents, they vary in size from small ones the size of a grain of rice to large ones the size of an egg. They are often diagnosed as lipomas, fibroids, etc. Sebaceous cysts grow very slowly, but patients can still feel that they are gradually increasing in size. Sebaceous cysts are mostly solitary, occasionally multiple, round in shape, moderately hard or elastic, above the skin surface, with a smooth surface that feels attached to the surface but not adherent to the base when pushed, and without a sense of fluctuation. The skin color may be normal or pale orchid, and the surface skin may shine when enlargement is too fast. Sometimes there is an opening on the surface of the skin from which white tofu-like contents can be squeezed out. This opening is where the opening to the sebaceous glands on the skin surface is located, and the depression of the opening is due to insufficient length of the duct. Sebaceous cysts are often complicated by infection, causing the cysts to rupture and temporarily subside, but they can form scarring and are prone to recurrence. The chance of sebaceous cysts becoming cancerous is extremely rare. Surgery is the only treatment for sebaceous cysts. During surgery, the skin attached to the cyst, especially when the duct opening is seen, can be removed along with the cyst by designing a shuttle-shaped skin incision in the direction of the skin line. Special care should be taken during the separation, as the cyst wall is very thin and should be removed as completely as possible. If the cyst wall remains, it is prone to recurrence. If there are inflammatory manifestations such as redness, swelling, heat and pain before surgery, the inflammation should be controlled first and surgery should be arranged later. Treatment principles 1.Surgical excision: once diagnosed, all cysts should be removed completely by surgery. 2.In case of co-infection, oral antibacterial drugs (such as synthroid tablets, methotrexate, etc.) and anti-inflammatory treatment such as hot compresses should be given, and surgical removal should be performed after the inflammation subsides.