[A case of MPO-ANCA positive hypertrophic pachymeningitis associated with vascular inflammation in the kidney biopsy].

We report a 76-year-old male with ANCA-associated hypertrophic pachymeningitis, who presented with crescentic glomerulonephritis. At the initial visit, he had episodic frontal headache and multiple cranial nerve palsy, including double vision, right deafness, hoarseness, and dysphagia. Because proteinuria and hematuria were detected on urinalysis, we performed a kidney biopsy, leading to the diagnosis of crescentic glomerulonephritis. The presence of vascular inflammation in the kidney biopsy led us to consider that this patient may show progression to the systemic type of MPO-ANCA-positive hypertrophic pachymeningitis. This proved useful for prognostic and treatment determination. Based on the results of laboratory tests, imaging studies, and biopsies of the dura mater and kidney, the patient was diagnosed with ANCA-associated hypertrophic pachymeningitis.