Incidental Malignant Colonic Polyp Detected in a Resected Ischaemic Large Bowel: A Case Report and Literature Review

Most patients with bowel cancer are symptomatic at the time of the diagnosis. They may present with a change in bowel habit, bleeding per rectum, abdominal pain, anaemia, weight loss or bowel obstruction. Colonic carcinoma can also be diagnosed incidentally during screening programs. Moreover, it may be incidentally detected in CT scans being performed for other indications or encountered during surgery for other causes. Some patients with colonic bowel ischaemia have associated large bowel cancer, where the ischaemic segment is usually proximal to the tumour and not necessarily associated with bowel obstruction. We are presenting a rare case of incidental malignant colonic polyp detected in a resected ischaemic large bowel in an 88-year-old gentleman. This was a very small tumour that was not visible macroscopically or detectable by imaging. Pathological examination of non-tumour colorectal resection specimens, as in this case, should include careful macroscopic examination and sequential block selection along the length of the colon, and where there is diffuse mucosal abnormality, block selection at 100mm interval is also advised. Attention to and block selection from any suspicious-looking area is warranted in all cases of non-tumour colorectal resections if such microscopic-sized malignancies of the type seen in our patient are to be picked up.