Shoulder MRI: What means? AC joint shows mild arthrosis w/cystic changes, predom. Clavicular w/mild surroundng edema.12x9x8 mm lesion seen w/in medial humeral neck, lobulated, compatible w/enchondroma

Benign. These findings are associated with arthritis. Depending on the type of daily activities you can develop these changes at a younger age. The "arthrosis w/ cystic changes" means that the joint space has changes in the cartilage that will lead to arthritis, which it seen at the clavicle; you have edema. An enchondroma is usually a benign bony cystic the bone but can predispose to fracture.