Differentiating primary angiitis of the central nervous system from paraneoplastic neurological syndrome.

Primary angiitis of the central nervous system (PACNS) is a rare, inflammatory condition affecting small- and medium-sized vessels in the brain and spinal cord. Its diagnosis presents challenges due to nonspecific symptoms that mimic various neurological and psychiatric disorders. This case underscores the diagnostic complexity of PACNS and its treatment difficulties. Although a brain biopsy remains the gold standard for diagnosis, its invasiveness, potential to exacerbate neurological deficits, risk of bleeding and potential damage to surrounding brain tissue make it impractical for all patients. In this case, standard glucocorticoid and immunosuppressive therapies failed to halt disease progression, demonstrating PACNS's typically poor prognosis. This case highlights the urgent need for improved diagnostic strategies and novel treatments to achieve better clinical outcomes.