Variable histopathology of discovertebral lesion (spondylodiscitis) of ankylosing spondylitis.

Extensive discovertebral lesion is an infrequent complication of long-standing ankylosing spondylitis. Reported histopathological descriptions vary from predominantly inflammatory to fibrous granulation with reactive bone formation. We report variable histological findings in four symptomatic patients with extensive discovertebral lesions who required spinal fusion.