Hypertrophic pachymeningitis is a characteristic manifestation of granulomatosis with polyangiitis: A retrospective study of anti-neutrophil cytoplasmic antibody-associated vasculitis

Abstract

Aim: To elucidate the characteristics of patients with hypertrophic pachymeningitis (HP) in a population with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Methods: We retrospectively investigated the clinical records of 39 patients who were diagnosed with AAV. To determine the characteristics of HP in AAV, the epidemiological and clinical data from patients with HP were statistically compared with those from patients without HP. Results: Of 39 patients with AAV, seven (17.9%) had associated HP. All patients with HP were classified as having granulomatosis with polyangiitis (GPA), whereas only five of 32 patients without HP were diagnosed as having GPA (P < 0.0001). The frequencies of myeloperoxidase (MPO)-ANCA and proteinase 3-ANCA positivity in patients with HP were equivalent, while MPO-ANCA positivity was obviously dominant in patients without HP. HP occurred as the initial clinical episode of AAV in three patients (7.7% of all AAV). Frequent significant characteristics of patients with HP were headache, cranial neuropathy and paranasal involvement (P < 0.05), and histopathological findings from paranasal involvement were useful for the diagnosis of GPA in some patients with HP. Combination therapy of corticosteroid and an immunosuppressant, such as methotrexate, cyclophosphamide or rituximab, was effective for achieving remission and improving radiographic findings of HP. Conclusion: AAV is a common cause of HP; epidemiological features of AAV patients with HP are different from those of patients without HP. Additionally, HP impacts diagnosis because it may be an initial clinical sign of AAV.