Shoulder cysts (a sac-like pocket of membranous tissue that contains fluid, air, or other substances) are swellings that arise around the socket of the shoulder joint (glenoid). A cyst may become very large and can press on important nerves around the shoulder. Compression of these nerves can lead to pain and weakness of the muscles in that region. This is a benign (non-cancerous) finding, and is likely due to degenerative (age related) changes in the shoulder.
The iliac is the hip bone. A bone island, also known as an enostosis, is a common incidental finding of a small area of dense bone inside the spongy part of the bone. Enostoses are common, present in up to 14% of individuals.The cause of bone islands is not known. They are most likely congenital (present from birth) or developmental in nature and are thought to represent either hamartomatous lesions (non-cancerous tumorlike malformations made up of an abnormal mixture of cells and tissues found in areas of the body where growth occurs) or failure of osteoclastic activity (the body's process of breaking down bone in order to build it up again) during bone remodeling. Bone islands are usually considered benign (non-cancerous), stable, nonprogressive lesions, with a preference for the long bones and the pelvis. They typically present without symptoms, do not cause pain and usually do not grow larger.
Ribs found fused together (also called rib synostosis) can either be congenital (from birth) or from past trauma. This is usually asymptomatic (does not cause symptoms), but can cause symptoms including a physical bump in the affected area, pain/numbness in the limb on the same side as the fusion, and difficulty taking a full breath.
The synovium is a thin membrane that lines the inner surfaces of joints and produces synovial fluid, which lubricates and protects joints from wear and tear. This fluid can sometimes build up and form a synovial cyst. Synovial cysts are benign (non-cancerous). Although their cause is not fully understood, they are often associated with osteoarthritis. Ganglion cysts are non-cancerous, fluid-filled lumps that can develop around joints and tendons in any part of the body, particularly the hand and wrist. Unlike synovial cysts, ganglion cysts do not have a synovial cell lining. Symptoms, if any, depend on the size and location of the synovial or ganglion cyst, and can include pain, numbness, tingling, weakness or trouble with joint movement.
Fat-containing tumors are the most common soft-tissue tumors encountered clinically with the vast majority being benign (non-cancerous). Lipomas are the most common type of fat-containing tumors and demonstrate a characteristic appearance on MRI. The cause is not fully understood, but there is a genetic factor as they typically run in families. Usually these tumors do not cause symptoms, but can become painful if large and pressing on nearby nerves. Diagnostic evaluation includes physical exam, biopsy (tissue sampling), and a dedicated CT or MRI. Treatment is not indicated unless the tumor is growing in size or causes pain, in which case it can be removed surgically. Fat-containing tumors may also resemble a form of cancer called liposarcoma (cancerous tumors in fatty tissues that grow rapidly, don’t move under the skin if pushed from side to side, and are usually painful). A biopsy and/or MRI or CT scan is typically performed if liposarcoma is suspected.
The hip is a ball-and-socket joint. The ball moves in the socket, allowing the leg to rotate and move forward, backward and sideways. As an individual ages, it is common for the cartilage (thin tissue that covers bone surfaces providing smooth, friction-free movement) in the hip joint to wear down. Degenerative hip joint changes can cause symptoms such as pain, stiffness, swelling around the joint, tenderness, limited range of motion, or a sensation of catching or grinding in the joint with movement.
