Background. Limited research is available regarding colorectal NENs and the prognostic factors remain controversial. Materials and Methods. A total of 68 patients with colorectal NENs were studied retrospectively. Clinical characteristics and prognosis between colonic and rectal NENs were compared. The Cox regression models were used to evaluate the predictive capacity. Results. Of the 68 colorectal NENs patients, 43 (63.2%) had rectal NENs, and 25 (36.8%) had colonic NENs. Compared with rectal NENs, colonic NENs more frequently exhibited larger tumor size (P < 0.0001) and distant metastasis (P < 0.0001). Colonic NENs had a worse prognosis (P = 0.027), with 5-year overall survival rates of 66.7% versus 88.1%. NET, NEC, and MANEC were noted in 61.8%, 23.5%, and 14.7% of patients, respectively. Multivariate analyses revealed that tumor location was not an independent prognostic factor (P = 0.081), but tumor size (P = 0.037) and pathological classification (P = 0.012) were independent prognostic factors. Conclusion. Significant differences exist between colonic and rectal NENs. Multivariate analysis indicated that tumor size and pathological classification were associated with prognosis. Tumor location was not an independent factor. The worse outcome of colonic NENs observed in clinical practice might be due not only to the biological differences, but also to larger tumor size in colonic NENs caused by the delayed diagnosis.

A 79-year-old man presented to our department with a 2-week history of urinary urgency and fever. His medical history was notable for multiple ileal ulcers that were diagnosed by colonoscopy 1 year ago; aspirin was considered as the cause and then was stopped. Laboratory studies included a white blood cell count of 33,000/mm 3 and urine white blood cell count of 11,292/mL. Meropenem, piperacillin/tazobactam, linezolid, and levofloxacin were administered according to a drug sensitivity test. Magnetic resonance urography showed an enterovesical fistula (Figure A, arrow) and air in the bladder (Figure B, arrow), which was confirmed by cystoscopy. Repair of the enterovesical fistula with ileocecal resection was performed. Pathology showed longitudinal fissuring ulcers extending to the serosa (Supplementary Figure A), suggestive of Crohn's disease. One year later, the patient developed another enterovesical fistula (Supplementary Figure B). Enterovesical fistulas are rare but serious complications of Crohn's disease. Pneumaturia and recurrent urinary tract infections are the most common symptoms. Enterovesical fistulas are difficult to treat and recurrence is common.

Abstract. Colorectal cancer is the third most common type of cancer worldwide, with >1 million cases diagnosed each year. Gastrointestinal bleeding is a common complication of colorectal cancer and is usually associated with the erosion and hemorrhage of the primary tumor. However, in patients who undergo a radical hemicolectomy and do not develop local recurrence, gastrointestinal bleeding may be a result of medical treatments or comorbidities. Esophageal bleeding in such patients is rare. Here, a case of severe esophageal bleeding due to anti-angiogenesis therapy with bevacizumab, and chemotherapy with the FOLFIRI regimen (irinotecan, folinic acid and 5-fluorouracil) in a patient with colorectal cancer is reported, and the possible pathogenesis of this event is analyzed based on the existing literature, in order to provide a reference for such cases.

Author Contributions: Drs Birnie and Wiersinga had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Drs Birnie and Biemond contributed equally.