This 92 year-old male patient presented for assessment of acute hemiparesis. An incidental finding was marked thickening of the calvarium. The diploic space is widened and there are ill-defined sclerotic and lucent areas throughout. The cortex is thickened and irregular. The findings probably correspond to the “cotton wool spots” seen on plain films in the later stages of Paget’s disease.

Paget’s disease is a chronic bone disorder characterised by abnormal bone remodelling. There are three stages classically described: lytic; mixed; and sclerotic. These stages correspond to scintigraphic stages: hot; intermediate; and cold. The aetiology is not known, however viral infection in association with genetic susceptibility has been postulated. Complications of Paget’s disease of the skull are often due to neural compression. Deafness is the most common complication. Cranial nerve paresis may occur. Basilar invagination may occur in advanced cases with hydrocephalus or brainstem compression. One percent of cases will develop a secondary sarcoma, which is often highly resistant to treatment.

2. Walsh J. Paget’s Disease of Bone. MJA 2004; 181 (5): 262-265

Credit: Dr Laughlin Dawes