ABSTRACT
The pathogenesis of granulomatosis polyangiitis (GPA), systemic vasculitis of small and medium-size vessels, is not completely understood. GPA mainly affects the upper and lower respiratory tract. However, it may involve the central nervous system (CNS) as well. The most common manifestation of CNS involvement is necrotizing vasculitis, leading to peripheral neuropathies or cranial nerve palsy. CNS disorder is less common. CNS involvement in GPA can manifest itself in three ways: Vasculitic involvement, granuloma spread from adjacent anatomical areas, and new granuloma formation in brain tissue. We present a case of GPA presented with diabetes insipidus.