The incidence and relevance of bone sclerosis in orbital pseudotumour

We reviewed the CT studies of 176 patients with biopsy-proven inflammatory pseudotumour of the orbit, in an attempt to establish the incidence of bone sclerosis in this condition. We found 20 patients (11.5%) to show definite bone sclerosis and/or hyperostosis, and in a further 10 (6%) there was probable sclerosis, giving a total of 30 patients (17%) with some evidence of bony change. Bone-window films were available for a minority of patients, and the frequency of sclerosis was therefore probably underestimated. This feature, which presumably represents a low-grade, chronic sterile osteitis, has not previously been emphasised.