A 69-year-old woman presented to our department with the chief complaint of diarrhea. She had undergone left nephrectomy for renal cancer 14 years earlier. Three years earlier, metastasis was detected in the left retroperitoneal cavity, and pazopanib administration was initiated. In the 29th month after the start of chemotherapy, the patient developed diarrhea, and on the 31st month, computed tomography showed thickening of the intestinal wall. Colonoscopy revealed white villi, intramucosal hemorrhage in the terminal ileum, and rough inflammatory mucosa with inflammatory polyps extending from the transverse to the sigmoid colon. Suspecting pazopanib-induced enteritis, we discontinued the medication, and the diarrhea resolved within 3 days. On the 21st day after discontinuation, colonoscopy revealed that the inflammatory polyps had shrunk, and the inflammatory findings had improved. Biopsy of the white villi of the ileum revealed histiocytes. The patient resumed treatment with pazopanib at 400 mg/day and developed soft stool on the 7th day after resumption. Compared with other tyrosine-kinase inhibitor-induced enteritis cases, this case showed less bleeding and more extensive inflammatory findings. There are similarities as well as differences from cases of previously reported pazopanib-induced enteritis. The mechanisms and characteristics of this disease require further investigation.

Drug-induced enteritis is an inflammatory disease changing in the morphology and function of the intestine as a result of medicine damage. With the increase in drug abuse in recent years, the incidence of drug-associated enteritis accordingly rises and becomes an important disease affecting the health and life quality of patients. Hence, elucidating the pathogenesis of drug-induced enteritis and finding cost-effective diagnostic and therapeutic tools have become current research focuses. The gut microbiota and metabolites regulate the immune response, playing a key role in the maintenance of homeostasis in the intestine. Numerous studies have found that many medicines can induce intestinal flora disorders, which are closely related to the development of drug-induced enteritis. Therefore, this paper analyses the role of gut microbiota and metabolites in regulating the immune response, and provides basic research direction and clinical reference strategies for drug-induced enteritis, taking into account the existing applications and perspectives.