IgG4 related disease of the craniovertebral junction

Background The majority of the abnormalities and diseases that affect the craniovertebral junction (CVJ) have already been reported, and therefore it is exceedingly rare to identify new pathology that affects the CVJ. Immunoglobulin G4–related disease (IgG4-RD) is an immune mediated process treated with immunosuppressive medications. To our knowledge, this is the first reported case of IgG4-RD affecting the CVJ. Case Description The authors report the case of a woman aged 71 years with IgG4-RD of the CVJ. She presented with intractable left occipital pain and limited flexion, extension, and rotation of the neck. Computed tomography and magnetic resonance imaging revealed a lytic enhancing lesion of the left occipital condyle, left C1 lateral mass, and left C1 anterior arch resulting in cranial settling, basilar invagination, and CVJ instability. An open biopsy, subtotal resection, and occiput to C2 fusion was performed. Pathology revealed IgG4-RD. The patient was subsequently placed on rituximab immunotherapy with complete resolution of enhancement on magnetic resonance imaging and bone growth at the previous site of the lytic IgG4-RD lesion. Conclusions To our knowledge, this case describes the first case of IgG4-RD affecting the CVJ, which mimicked a tumor-like process. When IgG4-RD affects the CVJ, stability must be accounted for, especially in the cases of osteolytic destruction. The combination of medical therapy to target the underlying inflammatory process and surgery to provide structural stability was successful.