Imaging-Guided Classification and Diagnostic Pathways for Appendiceal Abscesses: Results from the 2025 SIRC/SICUT Consensus Conference

Abstract Background. Imaging plays a pivotal role in the diagnosis and stratification of appendiceal abscess, a distinct phenotype of complicated appendicitis. Persistent heterogeneity in anatomical terminology, radiological grading, and diagnostic pathways continue to hinder reproducibility, clinical decision-making, and cross-study comparability. A standardized, imaging-centered framework integrating reproducible anatomical descriptors, validated severity grading, and evidence-based imaging strategies is therefore urgently needed. Methods. Under the auspices of the Italian Society of Research in Surgery (SIRC) and the Italian Society of Emergency and Trauma Surgery (SICUT), a multidisciplinary expert panel conducted a four-round modified Delphi process, culminating in an in-person consensus conference held in Rome on 6 November 2025. Statements were iteratively refined through anonymous voting, achieving predefined thresholds for consensus (≥80%) and strong consensus (≥95%). Results. The panel endorsed: (i) mandatory anatomotopographic classification of appendiceal abscess (pelvic, mesenteric, retrocecal/retrocolic, anterior with abdominal wall involvement); (ii) adoption of the Jeffrey radiological grading system (Grades 1–3: phlegmon/small abscess ≤3 cm; well-circumscribed abscess >3 cm; extensive/poorly defined with multi-compartment extension); and (iii) structured imaging recommendations. These include contrast-enhanced CT as the reference modality in adults, with selective use in suspected malignancy, particularly in patients >50–55 years, US-first/MRI-second pathways during pregnancy, and symptom-driven follow-up after conservative management. Conclusions. This consensus establishes a unified, imaging-guided diagnostic framework that harmonizes anatomotopographic localization with reproducible radiological stratification and pathway-oriented recommendations. Standardized definitions and structured reporting are expected to reduce practice variability, enhance interpretative consistency, and enable reliable cross-institutional and cross-study comparisons. These statements complement, rather than replace, clinical judgment and are aligned with recent international updates, including the 2025 WSES Jerusalem Guidelines. Prospective multicenter validation is warranted to assess their impact on clinical outcomes, drainage success, recurrence prediction, and the prognostic performance of the integrated anatomotopographic–Jeffrey approach.