Discordance Between Cross-Sectional Imaging and Pathology: A Rare Case of Xanthogranulomatous Inflammation of the Caecum and Appendix.

Cross-sectional imaging of colonic pathology is usually correlated with other investigations, such as optical colonoscopy (OC), prior to surgical treatment. However, in acute inflammation, surgery may proceed based on imaging alone. This case describes a 78-year-old woman presenting with dyspnoea, fatigue, and weight loss. An unprepared computed tomography (CT) of the abdomen and pelvis demonstrated evidence of caecal wall thickening suggestive of malignancy. Colonoscopy was omitted in this case due to the possibility of perforation, and an elective right hemicolectomy was subsequently performed. Results on histopathology inspection revealed xanthogranulomatous inflammation (XGI) without dysplasia or malignancy. While CT, including CT colonography, plays an increasing role in colorectal cancer (CRC) diagnosis and assessment, differentiating malignancy from benign inflammation on cross-sectional imaging alone remains challenging, and OC with biopsy remains the diagnostic gold standard. Although rare, especially in the context of the caecum and appendix, XGI should be considered by clinicians, radiologists and pathologists as a differential diagnosis when CRC is suspected clinically and radiologically, without biopsy confirmation.