IgG4-related hypertrophic pachymeningitis of the spine with MPO-ANCA seropositivity.

IgG4-related disease is an immune-mediated fibro-inflammatory condition that affects multiple organ systems. When the pachymeninges are involved, it is termed IgG4-related hypertrophic pachymeningitis (IgG4-RHP). We present a 79-year-old woman with back pain found to have IgG4-RHP localized exclusively in the spine who was also seropositive for myeloperoxidase anti-neutrophil cytoplasmic antibodies (MPO-ANCA). This case is the first known report of IgG4-RHP in the spine with MPO-ANCA and adds to emerging evidence for potential disease overlap in the pathogenesis of hypertrophic pachymenigitis (HP). We believe that increased awareness of this disease will result in an early diagnosis and initiation of life changing treatment.