University of Texas Southwestern Medical Center Dallas, TX
Samarth Shrivastava, MD, Neha Patel, MD University of Texas Southwestern Medical Center, Dallas, TX
Introduction: Immune checkpoint inhibitors (ICIs) may lead to immune-related adverse events (irAEs) in the gastrointestinal tract. Although ICI-induced colitis and diarrhea are well-documented, irAEs localized to the stomach are less frequently described. The management of most irAEs is suspension of ICI therapy and immune suppression; as only 0.2% of patients receiving ICIs have isolated ICI-induced gastritis, this is not well-documented in this population. This series presents two patients with isolated ICI-induced gastritis with complications and their responses to treatments.
Case Description/Methods: First, a 66-year-old male presented with stage III melanoma requiring nivolumab. After 8 cycles of therapy, he complained of diarrhea and vomiting of foul-smelling material. EGD and colonoscopy revealed an ulcerated fistula from the stomach to the colon with histology consistent with ICI-induced gastritis. After surgical resection, his symptoms completely resolved without immunosuppression. Second, a 60-year-old male presented with metastatic Merkel cell carcinoma requiring pembrolizumab. After two years of treatment, he endorsed early satiety and dyspepsia, with EGD revealing ICI-induced diffuse hemorrhagic gastritis and large ulcers (Figure 1). Conservative measures with a proton pump inhibitor and suspending pembrolizumab failed, with improvement only after several weeks of high-dose steroids and infliximab infusion.
Discussion: The first case describes an entirely novel entity: ICI-induced gastrocolic fistulation. The mechanism of ICI-induced gastritis is unclear but is theorized to be like inflammatory bowel disease. Transmural inflammation, a hallmark of Crohn’s disease, is required for fistula formation, suggesting a similar mechanism in ICI-induced gastritis. This case shows that immunosuppression is not always helpful for irAEs; our patient required surgical intervention. The second case highlights the effect of conservative management of ICI-induced gastritis. A conservative approach may be favored with irAEs by withholding ICI therapy and avoiding corticosteroids. Our patient’s hemorrhagic gastritis/ulcers were initially managed unsuccessfully with PPI and suspension of ICI therapy but required significant immunosuppression. This suggests the pathophysiology of ICI-induced ulcers is different from gastric ulcers due to disruption of barrier defense by H. pylori, nonsteroidal anti-inflammatory medications, and acid hypersecretion.
Figure: Figure 1. EGD revealed diffuse hemorrhagic gastritis in the cardia and greater curvature of the stomach. Three ulcers were noted. Pictured is the largest: a 9 mm ulcer on the greater curvature of the stomach,
Disclosures:
Samarth Shrivastava indicated no relevant financial relationships.
Neha Patel indicated no relevant financial relationships.
Samarth Shrivastava, MD, Neha Patel, MD. P4232 - Two Unusual Cases of Isolated Immune Checkpoint Inhibitor-Induced Gastritis, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.
