C-Anca Associated Cns Vasculitis - A Rare Presentation

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a necrotizing small-vessel vasculitis with infrequent central nervous system (CNS) involvement.CNS manifestations may occur through contiguous granulomatous spread, de novo intracranial granuloma formation, or primary vasculitic involvement of cerebral vessels [1], but are reported in only about 15% of patients with AAV [2].Isolated CNS involvement without systemic features is particularly rare and poses significant diagnostic challenges.We report a 20-year-old female with subacute progressive cerebellar symptoms over six months.Brain MRI demonstrated multiple T2/FLAIR hyperintense lesions involving deep gray matter and brainstem structures, with branching linear and nodular perivascular enhancement along Virchow-Robin spaces, without leptomeningeal enhancement.Cerebrospinal fluid analysis was non-inflammatory, infectious and granulomatous etiologies were excluded, and c-ANCA was positive.Based on clinicoradiological correlation and exclusion of alternative diagnoses, a diagnosis of probable c-ANCA-associated CNS vasculitis was made.Treatment with high-dose corticosteroids followed by rituximab resulted in significant clinical improvement.