Neutropenic Enterocolitis: New Insights Into a Deadly Entity.

Neutropenic enterocolitis (NE) is a deadly ileocecal-based disease seen in patients with a recent history of chemotherapy. As histology is not included in the current diagnostic criteria, the pathologic features of NE are poorly understood. We undertook a multi-institutional study of NE, and report helpful clinical clues, such as immunosuppression (n=20/20), recent chemotherapy (n=17/18), neutropenia (n=16/18) gastrointestinal symptoms (n=19/19), abnormal imaging studies of the cecum/right colon (n=11/14), and positive microbiological studies (n=13/15). Fever (n=9/15) and sepsis (n=8/16) were also common. Pathologically, the cecum/right colon was always involved (n=17/17), but findings were identified in other bowel segments as well. NE lesions consisted of patchy necrosis (n=18/20), infiltrating organisms (n=17/20), hemorrhage (n=15/20), ulcer (n=15/19), edema (n=15/20), and depletion of inflammatory cells (n=15/20). Seventy-nine percent (n=15/19) of patients with histologically confirmed NE died: 47% (n=7/15) of these deaths were attributed to NE and the remainder to the patients' underlying conditions. Importantly, we observed a clinical diagnostic discordancy rate of 35% (n=9/26): 15% (n=3/20) of histologically confirmed NE were clinically unsuspected, and 26% (n=6/23) of clinically suspected NE represented a different disease process. Alternative diagnoses included unspecified colitis, infection, graft-versus-host disease, relapsed malignancy, mycophenolate injury, appendicitis, and ischemia. The causes of death in patients with NE mimics included unrecognized appendicitis and unrecognized graft-versus-host disease. To improve diagnostic accuracy, we propose that histology be required for a diagnosis of "definitive NE," with other clinically suspicious cases reported as "suspicious for NE" until all other possible diagnoses have been reasonably excluded.