A case of small intestine inflammation after administration of an immune checkpoint inhibitor

Abstract

A 65-year-old malewith squamous cell carcinoma of the lungs developed hematemesis one month after starting treatment using atezolizumab as a 6^th-line therapy. Upper gastrointestinal endoscopy revealed mucosal erythema and erosions within the descending and horizontal legs of the duodenum. Similarly, capsule endoscopy showed mucosal erythema and erosions from the jejunum to the ileum. Moreover, histopathology demonstrated moderate neutrophilic infiltrate in the intrinsic layer of the duodenal mucosa,with regenerative changes in the epithelium. After treatment with steroids, colonoscopy showed no evidence of inflammation, including in the terminal ileum, and the patient's symptoms and endoscopic findings improved markedly.

This is a significant case in which ICIs could be reinstituted after the small intestine inflammation had improved. We report this case with respect to a review of the relevant literature.