Coexisting ankylosing spondylitis and Paget's disease

Summary The case of a 59-year-old man with definite HLA B27 negative ankylosing spondylitis (AS) and Paget's disease involving the skull, the right side of the pelvis and the proximal femur is reported. Fifteen cases with this coexistence have previously been described. Some of these, however, are patients with Paget's disease mimicking AS. It is emphasized again that attention must be paid to diagnosing AS in patients suffering from Paget's disease.