A mass is a palpable swelling that grows on a person’s body. Masses can occur anywhere on the body and can be found under the skin, commonly as lipomas and sebaceous cysts. Lipoma is a benign condition. Large lipomas are more than three centimeters in diameter and require surgical removal. Sebaceous cysts are hard masses with a tofu-like center and can have dark spots on the surface. Sebaceous cysts need to be surgically removed, and if they are not removed, they may develop secondary bacterial infections. Masses can also appear in the abdominal cavity, such as a mass on the liver, or a mass growing on the colon. A mass is a term used until the nature is clear. If the nature of the mass is clear, such as a colon mass pathologically confirmed to be a tumor, it is called colon cancer.