Local ischemia causes carcinoma-like changes of the rectum.

Purpose: Bioptic specimens of typical cancerous changes in the rectum usually reveal signs of malignancy. Our goal was to describe the clinical feature, histologic findings, and long-term outcome of patients in whom typical findings of carcinoma of the rectum were discovered by endoscopy, but whose histologic data did not confirm the diagnosis of a malignant disease.

Methods: We conducted a retrospective review of eight patients seen in our hospital with a clinical diagnosis of colorectal cancer.

Results: All patients had typical macroscopic findings of colorectal cancer. Endoscopic examination was performed because of chronic gastrointestinal symptoms (tenesmus, diarrhea, hematochezia, recurrent rectal prolapses; n = 5), incidental masses detected by rectal palpation (n = 2), or acute rectal bleeding (n = 1). Instead of confirming malignancy, all histologic specimens showed typical signs of intestinal ischemia. In three patients, tumors were removed by endoscopy; the other patients received symptomatic therapy. All patients were followed for an average period of 46 months. In five patients, symptoms disappeared completely. Three patients continued to suffer from intestinal discomfort. In one case, progression of ischemic damage led to subtotal stenosis, which necessitated proctectomy.

Conclusions: Our results indicate that, despite its rarity, "ischemic pseudocarcinoma" is an important differential diagnosis to cancer of the rectum. Prognosis is generally good. Only patients suffering from chronic symptoms may require surgical treatment.