The coexistence of ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis--a postmortem diagnosis.

A 72-year-old male was diagnosed as having ankylosing spondylitis, mainly according to radiological findings, confirmed as HLA-B27-negative. Postmortem examination of the skeleton raised doubts on the initial diagnosis, since spinal findings pointed out also to diffuse idiopathic skeletal hyperostosis. The authors discuss the differential diagnosis and enhance the postmortem findings which allowed the diagnosis of the two clinical entities in the same patient.