Soft bags growing in the flesh of the back of the hand may be caused by tendon sheath cysts, epidermoid cysts, lipomas and other diseases. 1. Tendon sheath cyst: the etiology is not clear, may be related to inflammatory stimulation, local strain and other factors. Patients will appear localized subcutaneous hemispherical bulge, smooth surface, soft, can be seen in the dorsal side of the wrist, dorsal side of the foot and other parts. 2. Epidermoid cysts: the etiology may be related to embryonic ectopic, skin injury and other factors. It mainly manifests as intradermal or subcutaneous nodules, which are single or several and can be moved, and can be seen in any part of the human body. 3. Lipoma: the etiology is not clear, it may be related to heredity, chronic inflammation, metabolic abnormalities and other factors. One or more lumps may appear under the skin of patients. Lipoma is soft and elastic in texture and can be seen in any part of the body where there is adipose tissue. There may be other causes of soft lumps in the flesh of the back of the hand, and it is recommended that the patient go to a regular hospital to clarify the cause of the disease and follow the doctor’s instructions for treatment.