Unsuspecting colon cancer

Recently, a gynecologist colleague called me about a patient of his: a 60-year-old female who was referred by a GP for right iliac fossa pain (pain in the lower right quadrant of the abdomen). There are many diagnostic possibilities but the commonest in a female is pain originating either from the ovary or appendix. The gynecologist had ordered a pelvic ultrasound followed by a pelvic MRI when it became apparent that the ovaries were normal in appearance. The MRI showed a 5cm cystic mass adjacent to the sigmoid colon. The diagnostic possibility at this point is an abscess arising from a colonic perforation.

When I saw the patient, she was quite well and no longer in pain. Her abdomen was soft and non-tender and I couldn’t feel any masses. What was worrisome was the fact that she was slightly anemic and her colon cancer tumor marker was raised.

I arranged for her to come into hospital where a CT scan of the abdomen was promptly done. This was in the hope that this would provide more information about the cystic mass, the bowel and digestive organs. The CT scan unfortunately did not provide much more details other than a slight thickening of the sigmoid colon suggestive of a malignancy. At this point, the lack of conclusive information was getting frustrating for the patient and I so we agreed that a flexible sigmoidoscopy would be done. This is a small procedure where a scope is passed up the colon to the location of the abnormality for a better assessment.

CT scan showing walled-off abscess
CT scan showing walled-off abscess

The flexible sigmoidoscopy showed a narrowed and stiff colon in keeping with the expected pathology of inflammation from a perforation. Associated with it was heaped-up mucosa suggestive of a malignancy or severe inflammation. Multiple biopsies were taken.

Back in the ward, I had a discussion with the patient and her family. We knew that there was certainly an abnormality in her colon highly suspicious of a perforated cancer. In the end, we agreed that a surgery to explore the abdomen was warranted with the aim to remove the affected colon and mass.

Surgery was done the next day. When I looked inside her abdomen, there was a large contained abscess (with moderate amount of pus) arising from the side of the sigmoid colon and stuck down onto the uterus, ovaries and bladder. I was able to resect that segment of the colon with the adjacent infected mass, the uterus and ovaries so as to ensure a complete clearance of the inflammation and presumed cancer. In the end, an anastomosis was performed to ensure continuity of her bowel. The operation lasted under 3 hours and she recovered well in the ward.

Cut up specimen showing the area of perforation and abscess cavity wall behind the colon
Cut up specimen showing the area of perforation and abscess cavity wall behind the colon

The final histology of the specimen showed perforated mucinous adenocarcinoma of the colon with several lymph nodes involved. Fortunately for her, the cancer is now completely removed. It is an aggressive cancer and she would now need to undergo chemotherapy to reduce the chances of a future recurrence.

This case is interesting in that the colon cancer did not present in the usual manner such as bleeding in the stools or a change in bowel habit. Other than a short episode of abdominal pain, she did not present with any alarming symptoms or signs. Despite the investigations that followed, the cancer remained elusive until the eventual surgery. The silver lining in the clouds is that she now has a good chance of a cure.

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