A hard lump on the leg can be seen in general surgery or orthopedics, because the most common diseases of hard lumps on the leg mainly include lipoma, sebaceous cyst or tendon sheath cyst. Lipomas or sebaceous cysts belong to general surgery and can be cured by removing them with local anesthesia. On the other hand, tendon sheath cysts are orthopedic diseases, which occur mainly due to joint hyperactivity, thus causing fluid accumulation in the joint capsule and the appearance of lumps. Tendon sheath cysts are usually treated conservatively, that is to say, to reduce activities. If the tendon sheath cysts can not be reduced after conservative treatment, or local hidden pain, swelling and other uncomfortable symptoms, you can consider surgery to remove the cysts, but there is a possibility of recurrence after surgery.