[MPO-ANCA-associated hypertrophic pachymeningitis with monoclonal gammopathy of undetermined significance: a case report].

A 66-year-old woman presented with dysesthesia over the right side of her face, hypoglossal nerve dysfunction, dysphagia, and dysgeusia of the right side. A MRI scan of the brain revealed cerebral dural thickening on the right side of the skull base, and histopathological examination revealed granulomatous inflammation of the dura. Based on paranasal sinusitis, bronchodilatation, laboratory tests showing weakly positive MPO-ANCA, intact renal function, and the patient's favorable response to steroids, we diagnosed the patient with limited granulomatosis with polyangiitis (GPA). Reportedly, autoimmune disease might occur in patients with exacerbation of monoclonal gammopathy of undetermined significance, which was observed in this case. This suggests the utility of immunoelectrophoresis.