A sliding lump in the chin is abnormal and is often caused by disease. Common causes include lipoma, enlarged lymph nodes, and submandibular cysts. 1. Lipoma: Lipoma is a common benign tumor of soft tissue, mainly formed by mature fat cells. Lipoma can grow in various areas with fatty tissue and is often associated with heredity, inflammatory stimuli and other factors. Patients may present with localized active lumps. 2. Enlarged lymph nodes: under the stimulation of microorganisms or other external factors, it may lead to inflammation of lymphatic tissues in the chin, and often leads to enlarged lymph nodes with pain. 3. Submaxillary cysts: Submaxillary cysts are cysts formed when the secretion duct of the sublingual gland is obstructed due to inflammation and other factors, and secretions accumulate. Patients often show symptoms of swelling in the chin, and those who are not in obvious condition may not be treated for the time being. When patients experience discomfort, they should go to the hospital immediately and follow the doctor’s instructions for treatment.