A hard bump on the leg can be seen in general surgery or orthopedics, because the most common diseases of hard bumps on the leg include mainly lipomas, sebaceous cysts or tendon sheath cysts. For lipomas or sebaceous cysts, which are general surgery diseases, they can be cured by removing them completely with local anesthesia. Tendon sheath cysts, on the other hand, are orthopedic disorders that occur mainly due to joint overactivity, which causes fluid to accumulate in the joint capsule and result in a mass. The tendon sheath cyst is usually treated conservatively, that is, to reduce the activity. If the tendon sheath cyst cannot be reduced after conservative treatment, or if there is local pain, swelling and other uncomfortable symptoms, surgery can be considered, but there is a possibility of recurrence after surgery.