Paget's disease of bone (osteitis deformans ) is the abnormal formation of bone tissue that results in weakened and deformed bones.

Paget's disease. Pagetic bone with an excessively high ratio of woven to compact bone is formed, causing spotty weakness in the Bone. The cause is unknown and may be viral. The disease usually localizes in the spine, pelvis, femur and skull.

From MedicineNet.com:

" Paget's disease is a chronic bone condition characterized by disorder of the normal bone remodeling process. Normal bone has a synchronized relationship of mechanisms that act to lay down new bone and take up old bone. This relationship (referred to as remodeling) is essential for maintaining the normal calcium levels in our blood. In bone affected by Paget's disease, the bone remodeling is disturbed and not synchronized. As a result, the bone that is formed is abnormal, enlarged, not as dense, brittle, and prone to breakage (fracture).

Paget's disease affects older bone of adults. It's estimated that 1% of adults in the U.S. have Paget's disease. There is an extremely rare form of Paget's disease in children, referred to as juvenile Paget's disease. Paget's disease is also known as osteitis deformans."

See related links below for the rest of the article.

Paget's disease of bone

The most common symptom of Paget's disease (osteitis deformans) is nonspecific bone pain.