Background: Primary angiitis of the CNS (PACNS) is a rare disease, limited to the brain and spinal cord, occurring in the absence of any evidence of systemic vasculitis, with significant morbidity and mortality [1].

Objectives: To evaluate clinical findings and radiological profile of a cohort of patients with PACNS.

Methods: This is a retrospective, single-center study (Immunoallergology Unit, University of Pisa) using data from a cohort of 25 patients between 2004 and 2024. The diagnosis of PACNS was made according to the Calabrese and Mallek criteria [2], using cerebrospinal fluid (CSF), brain MRI, angio-MRI, angiography, or biopsy. Secondary causes of vasculitis were excluded in all patients evaluated, indeed anti-nuclear antibody (ANA), anti–double-stranded DNA antibody, ASMA, anti-ENA, anti-neutrophil cytoplasmic antibodies, ACLA IgM, anti-beta2GPI and LAC resulted negative in all patient; in 2 patients (8%) ACLA IgG were detected at diagnosis but didn’t fulfil diagnostic criteria for antiphospholipid syndrome. We also ruled out infectious, neoplastic and other autoimmune connective diseases.

Results: Among the 25 patients evaluated 16 were female (64%), with a mean age at onset of 50.48 ± 11.54 years (range: 28-78 years). The symptoms duration before diagnosis was 1.52 ± 3.16 years. The main clinical manifestations included cognitive decline (44%), headache (40%), hemiparesis (40%) and speech disorders, such as aphasia or dysarthria (40%), followed by intraparenchymal haemorrhage (28%), seizures (20%), and visual symptoms (20%), including visual-field defects, blurred vision and diplopia. Brain MRI was performed in all patients and resulted abnormal in 92% of the patients, with multiple cerebral infarctions (28%), intracranial haemorrhages (36%), microhaemorrhages (36%). Angio-MRI was performed in 60% of the patients evaluated, of which 47% exhibited a typical pattern of alternating areas of stenosis and ectasia of the vessels. Cerebral angiography was performed in 80% of the patients and revealed the typical diagnostic pattern in 40% of the cases. Eight patients (32%) did not show typical vascular alterations on either angio-MRI or angiography. Among them, biopsy was performed only in one patient, while the other 7 patients still had clinical presentation and radiological findings characteristic of PACNS as well as response to treatment. Therefore, they were classified as “probable PACNS”. A biopsy on abnormal brain tissue on imaging was performed in 16% of the patients, yielding non-diagnostic results in one case (25%). Small vessel involvement with a lymphocytic histological pattern was confirmed in 2 patients (50%). One patient showed a lymphocytic pattern at the biopsy, but with a radiological pattern typical of large/medium vessel involvement.

Conclusion: Our study highlights the different clinical and radiological features of PACNS in a monocentric cohort. The multidisciplinary approach among neurologists, neuroradiologists, rheumatologists and immunologists remain crucial in the diagnosis and management of PACNS. Furthermore, MRI and angiographic imaging are fundamental to perform diagnosis and monitoring this rare condition. Although brain biopsy is an invasive procedure, it continues to play a key role in the diagnosis of PACNS, particularly in patients with normal angiography [3]. The prognosis of PACNS remains variable, but early diagnosis is crucial for better outcomes, particularly given the need for prompt treatment with high-dose intravenous steroids, either alone or in combination with immunosuppressants [4].

REFERENCES: [1] Birnbaum J, Hellmann DB. Primary angiitis of the central nervous system. Arch Neurol. 2009 Jun;66(6):704-9. doi: 10.1001/archneurol.2009.76. PMID: 19506130.

[2] Calabrese LH, Mallek JA. Primary angiitis of the central nervous system. Report of 8 new cases, review of the literature, and proposal for diagnostic criteria. Medicine (Baltimore). 1988 Jan;67(1):20-39. doi: 10.1097/00005792-198801000-00002. PMID: 3275856.

[3] Salvarani C, Hunder GG, Brown RD Jr. Primary Central Nervous System Vasculitis. N Engl J Med. 2024 Sep 19;391(11):1028-1037. doi: 10.1056/NEJMra2314942. PMID: 39292929.

[4] Pizzanelli C, Catarsi E, Pelliccia V, Cosottini M, Pesaresi I, Puglioli M, Moretti P, Tavoni A. Primary angiitis of the central nervous system: report of eight cases from a single Italian center. J Neurol Sci. 2011 Aug 15;307(1-2):69-73. doi: 10.1016/j.jns.2011.05.014. Epub 2011 Jun 1. PMID: 21636100.

Acknowledgements: NIL.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.