Spinal Bony Involvement of IgG4-related Disease Treated by a Spondylectomy.

Immunoglobulin G4-related sclerosing disease (IgG4RD) is an emerging immune-mediated fibro-inflammatory disorder which can involve any organ. We describe the first IgG4-RD spondylitis treated with total en-bloc spondylectomy (TES). A 55-year-old man presented with back pain. Magnetic resonance imaging (MRI) of the thoracic spine revealed a pathologic compression fracture on T11 vertebral body and both pedicles suggestive of primary bone tumor or bone metastasis. We conducted TES of T11, because we could not exclude the possibility of primary bone tumor including giant cell tumor. Immunohistochemical examination of the pathology specimens from pleura around the pedicle demonstrated diffuse infiltration of IgG4-bearing plasma cells. Six weeks later from the surgery, a delayed serologic test was done and his serum IgG4 concentration was 45 mg/dL. The final diagnosis was probable IgG4RD on the basis of serological, imaging, histopathological findings. After 6 weeks of oral prednisolone treatment, patient's back pain improved dramatically. IgG4RD is very rare systemic disease and its paraspinal soft tissue like pleura involvement with vertebra body invasion was absent until now. Our experience indicated that surrounding soft tissue biopsy would be helpful when a percutaneous vertebra bone biopsy mismatched with the image studies, even though vertebra body was main pathological lesion considering the possibility of IgG4RD.