Characteristics of hypertrophic pachymeningitis in patients with granulomatosis with polyangiitis

Hypertrophic pachymeningitis (HP) is an important neurologic complication of granulomatosis with polyangiitis (GPA, formerly Wegener's granulomatosis). The aim of this study is to investigate the clinical features, radiological findings, and diagnostic pitfalls of GPA-related HP. A retrospective chart review was performed to screen patients diagnosed with GPA at Samsung Medical Center between 1997 and 2016. Neurologic manifestation, laboratory findings, neuroimaging data, and clinical course were evaluated in all patients. Characteristics of patients with HP were compared to those of patients without HP. Sixty-five patients with GPA were identified. Twenty-five of these patients had central nervous system involvement. HP (N = 9, 36%) was the second most common radiologic finding. Other neurologic findings included stroke (N = 7, 28%) and granulomatous disease (N = 10, 40%). Patients with HP had lower incidences of systemic manifestations (N = 2, 22.2% vs. N = 38, 67.9%, p = 0.013 in the lung and N = 1, 11.1% vs. N = 28, 50.0%, p = 0.030 in the kidney) than those without HP. Six patients with GPA-related HP were MPO-ANCA positive (66.7%) and two had PR3-ANCA (22.2%). Most of the patients with HP presented with headache (N = 8, 88.9%) at a rate that is similar to those of primary headache disorders (migraine, tension-type, and stabbing) and other secondary headache disorders (postural type and meningitis). Patients with HP rarely had neurologic deficits (N = 3, 37.5%). Different clinical or radiologic features may be observed in GPA-related HP. Early recognition and accurate diagnosis of GPA-related HP are needed in addition to neuroimaging findings.