Discussion

Diagnosis

Mass-forming ischemic colitis.

Discussion

Ischemic colitis (IC) is a common vascular disorder of the intestines, predominantly affecting older patients. IC accounts for 50–60 percent of all gastrointestinal ischemic episodes, more frequently in the absence of major vessel occlusion. The pattern of injury is most commonly segmental, primarily involving the “watershed” zones of the splenic flexure, descending colon, and the rectosigmoid junction; however, any part of the colon may be affected. Often, the diagnosis can be made utilizing clinical, radiologic, colonoscopic and mucosal biopsy findings; however, there have been reports of atypical pathologic manifestations, precluding the diagnosis. IC is the result of reduced vascular perfusion leading to mucosal injury through hypoxia/reperfusion injury. Clinically IC typically presents acutely with abdominal pain, hematochezia and diarrhea. Depending on the duration and extent of colonic injury, more serious complications such as fever, perforation, peritonitis and septic shock can develop. While there are occlusive and non-occlusive etiologies, with varied clinical presentation, all demonstrate similar histologic features. In rare cases IC may form a mass-like lesion, mimicking malignancy.

Correlation with colonoscopy and mucosal biopsies is required in certain instances to rule out malignancy, including when barium enema identifies strictures showing areas of luminal narrowing or filling defects due to ischemia. Clues to the diagnosis of this clinicopathologic variant of IC include: acute onset, rapidly changing course, elderly female patient, location in the right colon, ischemic colitis on histology after thorough sampling, and discordant imaging and colonoscopy findings. Histologic evaluation demonstrates lamina propria hyalinization and hemorrhage, a variable degree of epithelial damage in the form of mucin depletion, crypt atrophy and loss, additionally edema and fibrosis of the submucosa and muscularis propria is observed. Literature has described few patients who have undergone colectomy, with histologic findings limited to submucosal and/or mural edema or submucosal fibrosis. Therefore, it is important to ensure adequate evaluation of the patients’ clinical and histologic findings which are is instrumental to avoiding a more extensive treatment. As in our case, these patients can often be managed conservatively with resolution of the mass-like lesion on follow-up studies. It is important for both pathologists and gastroenterologists to be aware of this variant of IC to avoid unnecessary surgery.

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References

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