Two common types of masses in the hand: This article focuses on two common masses in the hand to give you an idea. I. Tenosynovial cysts are very common non-neoplastic masses in the wrist, immediately adjacent to the tendon, muscle or joint capsule. It can appear on the joint capsule, tendon sheath and ligament in several parts of the body, but has the highest incidence in the wrist. The cause is uncertain, but is thought to be related to pars interarticularis connective tissue dystrophy, degenerative changes and mucus degeneration. The capsule is a jelly-like viscous fluid composed of hyaluronic acid and proteins, and the wall is dense, tough fibrous connective tissue without true synovial epithelium. Ultrasound manifestations: 1, round or oval. 2, The wall of the capsule is smooth, and the interior is echogenic with clear echogenicity and posterior enhancement effect. 3, generally no internal separation, old cysts have increased internal echogenicity, visible separation, and some solid-like changes. Giant cell tumor of the tenosynovial sheath is the second most common mass in the wrist, benign, also known as yellow pigment tumor or benign synovial tumor, slow-growing, common in middle-aged and elderly people, mostly occurs in the metacarpophalangeal joint and its distal end, the etiology is unclear, may be related to trauma and cholesterol metabolism, manifests as a local hard and tough mass, can feel slight pain and pressure pain, can be multiple adhesions along the tenosynovial sheath resulting in inability to extend the knuckles, can grow into the joint capsule, can grow around the nerve Ultrasound: 1. mass-like or lobulated. 2. 2, solid hypoechoic, moderate hypoechoic nodules. The boundary is clear, the mass is closely related to the tendon and can encircle it, and it can invade the adjacent bone, and the local defect of bone cortex is detected. 4, the general blood flow signal is sparse, and some of them can be seen in speckle-like and dendritic distribution.