Highlights from the breakout session: diagnosis and classification of vasculitis.

The session on 'Diagnosis and Classification of Vasculitis' featured six oral presentations covering various aspects of vasculitis diagnosis and classification. The application of the Ankara criteria for IgA vasculitis in adults was evaluated, finding that while the criteria showed good sensitivity, their specificity was insufficient, suggesting the need for refinement. A clustering approach to classifying ANCA-associated vasculitis (AAV) identified five distinct clusters, which improved prediction of disease outcomes. The performance of the new 2022 ACR/EULAR classification criteria was tested in a Spanish cohort, revealing reclassification of patients mainly based on ANCA subtype. The importance of standardized histopathological assessment in giant cell arteritis (GCA) was highlighted, while research on a tissue-mimicking phantom demonstrated its potential for ultrasound training. Finally, a study showed that prolonged [18F]FDG-PET/CT acquisition times improved diagnostic specificity for GCA. These findings underscore the need for continuous refinement of classification criteria and diagnostic techniques in vasculitis research and clinical practice.