Pathology: imbalance between formation and resorption of bone.

Diagnosed at autopsy in 3% of patients older than 40. Onset age 30 to 70.

Symptoms and signs: result from (a) arteriosclerosis (a common accompaniment of Paget disease); (b) pressure on CNS or nerve roots by bony overgrowth. Most common symptoms: deafness (pressure on auditory nerves), unilateral facial palsy, monocular visual loss, spinal cord compression.

Laboratory data: normal serum calcium, increased serum alkaline phosphatase. Skull radiograph: areas of increased bone density with loss of normal architecture, mingled with areas of decreased bone density (“cotton wool” appearance).