Title : Macroscopic assessment of acute appendicitis versus histopathological diagnosis: A clinical audit of diagnostic concordance
Abstract:
Background: Intraoperative macroscopic assessment of the appendix influences surgical decisionmaking and provides an immediate estimate of disease severity; however, visual assessment may not reliably correspond with definitive histopathology. Misclassification may result in removal of histologically normal appendices or under-recognition of complicated disease. This audit evaluated agreement between intraoperative macroscopic appearance and postoperative histopathological diagnosis in patients undergoing appendicectomy.
Methods: A retrospective clinical audit was undertaken of 120 consecutive appendicectomy cases recorded within a single institutional dataset. Macroscopic operative findings were classified as normal appendix, simple appendicitis, or complex appendicitis (gangrenous or perforated) and compared with definitive histopathology. Three patients without histopathological examination were excluded from pathological comparison. One patient with parasitic pathology was excluded from the three-category concordance analysis, leaving 116 cases. Overall agreement and Cohen's kappa were calculated. Diagnostic performance was additionally assessed for identifying any histological appendicitis and for recognising complex appendicitis.
Results: Among 116 evaluable cases, macroscopic and histopathological classification was identical in 97 (83.6%). Agreement beyond chance was substantial (Cohen's kappa=0.707; linearly weighted kappa=0.743). Fourteen of 15 macroscopically normal appendices were histologically normal, while one demonstrated simple appendicitis. Of 72 appendices classified macroscopically as simple appendicitis, 60 were confirmed as simple disease, four were upgraded histologically to complex appendicitis, and eight were normal. Among 29 macroscopically complex cases, 23 were confirmed as complex and six were downgraded to simple appendicitis. For discrimination of any appendicitis from a normal appendix, macroscopic assessment demonstrated 98.9% sensitivity, 63.6% specificity, 92.1% positive predictive value, 93.3% negative predictive value, and 92.2% overall accuracy. For complex appendicitis, sensitivity was 85.2%, specificity 93.3%, and positive predictive value 79.3%.
Conclusions: Intraoperative macroscopic assessment demonstrated substantial agreement with definitive histopathology and was highly sensitive for the presence of appendicitis. However, specificity was comparatively limited, predominantly because macroscopically inflamed appendices were occasionally histologically normal. Clinically relevant discordance also occurred in grading disease severity, with both under- and over-classification of complex appendicitis. These findings reinforce histopathology as the definitive diagnostic standard and support routine pathological examination following appendicectomy. Standardised intraoperative documentation and prospective re-audit may improve diagnostic consistency and clarify factors associated with macroscopic-histological discordance
