IgG4 related disorders of the CNS – A neurosurgeons perspective

IgG4-related diseases (IgG4-RD) are immune-mediated fibro-inflammatory conditions that can mimic various other diseases and affect multiple organs, including the central nervous system (CNS). This case series examines five patients with diverse CNS manifestations of IgG4-RD. A 30-year-old man presented with spinal cord compression and was diagnosed with IgG4-related spinal pachymeningitis following surgical excision and elevated serum IgG4 levels. A 16-year-old girl with bitemporal hemianopia and panhypopituitarism was initially diagnosed with hypophysitis but later found to have IgG4-related sellar disease upon positive immunostaining despite normal serum IgG4 levels. A 40-year-old man with recurrent orbital pseudo-tumour and vision loss was ultimately identified as having IgG4-related orbital disease, complicated by active tuberculosis, and treated with a combination of anti-tuberculous therapy and Rituximab. A 37-year-old woman with post-COVID visual symptoms and suspected fungal infection was diagnosed with IgG4-related pachymeningitis and treated with cyclophosphamide and Rituximab. Lastly, a 21-year-old woman with drug-resistant epilepsy and a frontal brain lesion was diagnosed with IgG4-related intraparenchymal disease, responding well to corticosteroid therapy. This series highlights the varied presentations and diagnostic challenges of IgG4-RD in the CNS.