FP4.4 - Everything is not always as it seems – Discordance between cross-sectional imaging and pathology. A case report

Abstract Cross-sectional imaging of colonic pathology is usually correlated with other investigations such as optical colonoscopy (OC) prior to surgical treatment. In situations such as acute inflammation, this is not possible and surgery is undertaken based on cross-sectional imaging without histopathological confirmation. This case reports describes a 78-year-old female who presented with progressive shortness of breath associated with fatigue and unintentional weight loss. Initial bloods demonstrated a normocytic anaemia (Hb 105g/L, MCV 86fl), raised D-dimer (3460ng/mL) and raised C-reactive protein (133mg/L) with normal white cell count (8.6 x109/L). An unprepared computed tomography (CT) of the abdomen and pelvis revealed extensive bowel thickening in the caecum with radiological appearances consistent with a primary caecal malignancy. Preoperative colonoscopy was not performed as suspicion of perforation on CT imaging precluded the use of mechanical bowel preparation. Preoperative optimisation of the patient was commenced and an elective right hemicolectomy performed. The patient had an uneventful post-operative recovery. Results on histopathology inspection revealed chronic xanthogranulomatous inflammation but no macroscopic or microscopic evidence of dysplasia or malignancy. There continues to be an emerging role for the use of CT imaging, especially CT colonography, in the investigation and diagnosis of CRC. However, difficulty in distinguishing between malignant and non-malignant inflammation on CT endorses the quintessential place of OC with biopsy as the definitive investigation of CRC, especially if suspicion of CRC on unprepared CT. Xanthogranulomatous inflammation should be considered by clinicians, radiologists and pathologists as a differential diagnosis when CRC is suspected clinically and radiologically, without biopsy confirmation.