Granulomatosis with polyangiitis (GPA) is a vasculitic disease with an infrequent involvement of the central nervous system. This can lead, in rare cases, to hypertrophic pachymeningitis (HP), which is characterized by inflammation and fibrosis that cause a thickening of dura mater. At present, it is crucial to consider GPA in the differential diagnosis of elderly patients with intracranial hypertension. The case is presented of a 60-year-old male with progressive severe headache, vomiting, and wasting syndrome. Physical examination showed pallor, weight loss, and unilateral papilloedema. A gadolinium-enhanced brain MRI scan showed sinusitis, chronic otomastoiditis, and hypertrophic pachymeningitis. Finally, a meningeal biopsy concluded a necrotising granulomatous vasculitis compatible with GPA. However, PR3- and MPO-ANCA were negative. After corticosteroid therapy was initiated, the patient had a favorable outcome during his hospital stay.