Mass-forming Ischemic Colitis that Mimics Colon Cancer

Ischemic colitis is a condition characterized by reduced blood flow to the colon, leading to inflammation and injury of the intestinal tissue. While it typically presents with symptoms such as abdominal pain, diarrhea, and hematochezia, there are rare instances where ischemic colitis can mimic the appearance of colon cancer. This article explores two cases of mass-forming ischemic colitis that were initially suspected to be malignancies, highlighting the diagnostic challenges and the importance of a conservative approach in such scenarios.

Case Presentations

Case 1: A 78-Year-Old Male with Suspected Hepatic Flexure Cancer

A 78-year-old male was referred to the outpatient clinic with abdominal pain and a suspicion of hepatic flexure cancer. His medical history included hypertension, diabetes mellitus, and chronic kidney disease. He was also a heavy smoker and an alcoholic. Prior to admission, a non-contrast CT scan (due to his chronic kidney disease) and a colonoscopy were performed at a local clinic.

The CT imaging revealed segmental wall thickening of the proximal ascending colon with pericolic infiltration. Colonoscopy showed an ulcero-infiltrative mass-like lesion, and a biopsy was performed. The histopathology results indicated chronic inflammation with reactive changes and necrotic inflammatory exudate. Although these findings did not definitively suggest malignancy, cancer was strongly suspected. The patient’s carcinoembryonic antigen (CEA) level was normal.

Approximately one month after the initial colonoscopy, laparoscopic surgery was performed. The intraoperative camera images revealed wall thickening, prompting a laparoscopic right hemicolectomy. However, the gross surgical specimen showed no lesion. The final pathology report confirmed segmental submucosal fibrosis, indicative of a healed ulceration.

Case 2: A 66-Year-Old Female with Hematochezia

A 66-year-old female presented to the outpatient clinic with hematochezia. Her medical history included diabetes mellitus. Colonoscopy revealed a 4-cm ulcero-infiltrative mass in the splenic flexure. A biopsy showed necrotic inflammatory exudate without epithelial cells. A CT scan revealed diffuse wall thickening with serosal infiltration. The patient’s CEA level was also normal.

Given the suspicion of malignancy, surgery was performed three weeks after the colonoscopy. However, no tumor was found during the procedure. An intra-operative colonoscopy confirmed the diagnosis of ischemic colitis, and the surgery was completed without any resection.

Discussion

Diagnostic Challenges

The most critical aspect of diagnosing mass-forming ischemic colitis is differentiating it from malignancy. This can be particularly challenging because the endoscopic and imaging findings often resemble those of carcinoma. In both cases presented here, colonoscopy and CT imaging showed ulcero-infiltrative masses suggestive of malignancy. However, biopsies revealed only inflammation with reactive changes, which did not confirm cancer.

Biopsies can sometimes be inadequate, making it difficult for surgeons to decide whether to proceed with immediate surgery or to re-evaluate after a few weeks. As demonstrated in these cases, unless there are other clinical reasons for emergency resection, a conservative approach with repeat colonoscopy or imaging may be more appropriate.

Clinical and Pathological Features

Khor et al. reported the clinical and pathological features of mass-mimicking variants of ischemic colitis. Among 19 patients, all were initially suspected of having malignancies, with polypoid or fungating masses obstructing the lumen in 16 cases. The mean mass size was 4.67 cm. CT scans showed segmental thickening suspicious for malignancy in six of eight patients, and colectomy was performed in four cases due to suspicion of malignancy. Follow-up colonoscopies performed between 1 and 32 weeks after initial presentation showed resolution of the masses in all cases.

Anatomical Distribution

The typical location of injury in ischemic colitis involves the “watershed” zones of the splenic flexure, descending colon, and the rectosigmoid junction. However, in mass-forming ischemic colitis, lesions are often found in the cecum and ascending colon, as seen in Case 1. This distinct anatomical distribution suggests that mass-forming ischemic colitis may have a different pathogenesis compared to the usual forms of ischemic colitis.

Management Strategies

If surgery is recommended based on strong suspicion of malignancy from colonoscopy and CT imaging, but without clear pathological findings, extra care is necessary. If the patient does not develop severe symptoms such as persistent bleeding or perforation, a conservative approach with careful reevaluation of symptom changes and repeat colonoscopy should be considered before surgical intervention. Intra-operative colonoscopy, as used in Case 2, can also help determine whether resection is necessary.

Conclusion

Mass-forming ischemic colitis that mimics colon cancer presents a significant diagnostic challenge. The distinction between this type of colitis and malignancy is difficult, but careful history-taking and biopsy findings from a well-sampled lesion are essential for an accurate diagnosis. Awareness of this resemblance and the use of a conservative approach with repeat and intra-operative colonoscopy can help prevent unnecessary surgery.

doi.org/10.1097/CM9.0000000000000800

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