Paget's Disease

A 74-year-old man, who had been aware of a gradual increase in hat size over the past 3 years, complained of a mild headache and backache. His serum phosphatase level was 1,475 U/L (upper normal limit, 120 U/L). Skull films showed calvarial enlargement caused by thickening of the cortical tables, radiolucency in the frontal and occipital regions, and patchy osteosclerosis that produced a cotton-wool appearance.