Case Report: Unilateral relapsing primary central nervous system vasculitis-expanding the phenotype

Area of Science:

• Neurology
• Immunology
• Vascular Medicine

Background:

• Unilateral relapsing primary central nervous system vasculitis (UR-PCNSV) is a rare subtype of primary central nervous system vasculitis (PCNSV).
• It is characterized by recurrent inflammatory lesions confined to a single cerebral hemisphere.
• This study expands the known phenotype of UR-PCNSV by adding three new cases to the literature.

Observation:

• Three biopsy-proven UR-PCNSV cases were identified with recurrent, unilateral lesions.
• Patients presented with headache, unilateral neurological deficits, and cognitive impairment.
• Cerebral angiography was normal, but MRI revealed parenchymal and leptomeningeal enhancement.

Findings:

• UR-PCNSV cases exhibited a younger age of onset and frequent relapses compared to typical PCNSV.
• Biopsies showed a T-cell predominant lymphocytic infiltrate with transmural inflammation and necrosis.
• Despite anti-CD20 monoclonal antibody therapy, relapses occurred, necessitating prolonged immunosuppression.

Implications:

• UR-PCNSV demonstrates high inflammatory activity, evidenced by persistent enhancement and early hemiatrophy.
• Aggressive and prolonged immunosuppression is crucial for managing this rare PCNSV subtype.
• Overlapping features with CNS demyelination can cause diagnostic delays, underscoring the need for careful evaluation.