Paget's disease is a long-lasting (chronic) disorder that causes
abnormal bone growth. Paget's disease most often affects the bones in the
pelvis, spine, skull, chest, and legs.
In healthy people, bone is constantly being replaced as bone tissue
is broken down and absorbed into the body, then rebuilt with new cells. In the
early stages of Paget's disease, bone tissue breaks down faster than it
rebuilds. To make up for this breakdown process, the body speeds up the
rebuilding process. This new bone, though, is often weak and brittle, causing
it to break (fracture) more easily.
Most cases of Paget's disease do not cause symptoms. But the
most common symptoms, when they occur, are bone pain and deformed bones (bowed
legs, enlarged skull or hips, or a curved backbone).
Paget's disease is most common in middle-aged and older adults. It
may be treated with medicines or, in rare cases, with surgery.