Some friends may unintentionally find a round, smooth surface swelling at the wrist or the back of the hand, which is painful when pressed, and then they start to worry, what is this thing? 1, tumor, benign or malignant? In fact, this is a disease called tendon sheath cyst, which is a benign mass containing jelly-like mucus that occurs near the joint capsule or tendon sheath, and is mostly unicompartmental, but can also be multicompartmental. 2.What is the cause of the disease? It may be related to chronic trauma. Some occupations that require long-term repetitive work, such as typists, cargo handlers or industries that require long hours of computer operation, may trigger or aggravate this disease. Currently, there are two types of treatment: surgical and conservative. The principle of conservative treatment is to make the contents of the capsule discharged, inject drugs or leave a sterile foreign body that can be removed in the capsule, and pressure bandage, so that the capsule cavity adhesions and disappear, this method is simple, less painful, but also has a certain recurrence rate, surgery is generally applicable to the finger tendon sheath cyst or multiple recurrence of tendon sheath cyst operation is simpler, the recurrence rate is low.