A case of IgG₄oligoarthritis mimicking psoriatic arthritis

Abstract

IgG-related disease (IgG-RD) is a rare but rapidly emerging immune-mediated fibroinflammatory condition that can affect almost any organ. It is typically associated with involvement of organs such as lymph nodes, submandibular glands, orbits, periaortic region and pancreas. However, IgG-RD presenting primarily as an inflammatory arthritis is much less recognised. We present a rare case of IgG-RD mimicking psoriatic arthritis. In spite of normal circulating IgG plasma levels, a clinical index of suspicion was required to obtain a histopathological diagnosis. The patient's aggressive arthritis disease did not initially respond to typical disease- modifying agents such as methotrexate. Instead, we report a dramatic response to B cell depletion with rituximab. It is important to emphasise this case as a rare presentation of a rare disease. IgG-RD is a rapidly emerging condition and the diagnosis should be considered when the alternatives do not seem to fit.

Immunoglobulin G4-related spinal pachymeningitis

“…5 This case was recognized as a spinal cord compressive epidural mass, and the patient underwent decompression spinal surgery after 2 years from his initial complaint in outpatient clinic attendance. Also, the IgG4-related disease rarely manifested as polyarthritis, which mimicked psoriatic arthritis as reported in one case only, 6 but also can mimics rheumatoid arthritis as in our case, which has not been previously reported. Magnetic resonance imaging findings in IgG4related disease spinal involvement in the previous reported cases mostly affects cervical and thoracic vertebrae with sparing of intracranial area.…”