There are various causes for a hard bone like bump on the top of the foot, the most common cause is due to a tendon sheath cyst. It is mainly caused by repeated friction of the strained tendon and is accompanied by pain, redness and swelling, and can be examined by ultrasound. If the symptoms are severe, they can be removed surgically under the guidance of a doctor. It may also be due to the friction between the surface of the foot and the shoe, which causes the sebaceous gland to metabolize abnormally, causing the sebaceous gland to proliferate and thus forming a sebaceous cyst. In addition, it may be a lipoma. A lipoma that develops slowly on a small foot does not need to be treated if there are no other symptoms, but if it is larger, it needs to be removed, and laser removal is an option. In addition, it may also be an unexplained subcutaneous nodule, the specific circumstances need to go to the hospital to confirm the nature and then decide whether the need for timely treatment of symptomatic treatment. In addition, we need to pay attention to rest, pay attention to the protection of the affected area, and carry out reasonable conditioning to minimize the damage to the body.