Erosive arthritis of the costovertebral joint in seronegative spondyloarthropathy.

A 50-year-old male presented with polyarthritis and pain of the right costovertebral angle in the cervicothoracic area. Radiological findings in a sacroiliac joint, the presence of a syndesmophyte, the HLA B-27 phenotype and negative serological studies prompted the diagnosis of HLA-B27 related seronegative spondyloarthropathy. Conventional and computerized tomograms disclosed an erosive arthritis of the 1st right costovertebral joint that was responsible for the pain in the costovertebral angle. We are unaware of previous CT scan documentation of such lesions.