A case of HCC successfully treated with infliximab‐steroid sequential therapy for small bowel perforation due to atezolizumab/bevacizumab combination therapy

BACKGROUND: Although reports of gastrointestinal perforation after immune‐related adverse events (irAE) enteritis are rare, the anti‐ vascular endothelial growth factor (VEGF) effect of bevacizumab may be involved in gastrointestinal perforation. We report a rare case of gastrointestinal perforation in a patient with hepatocellular carcinoma treated with atezolizumab/bevacizumab combination therapy and infliximab before steroid use. CASE: A 72‐year‐old man, who received seven courses of atezolizumab/bevacizumab for hepatocellular carcinoma due to hepatitis B, was admitted to our department with idiopathic abdominal pain and diarrhea (grade 2 [G2]). Computed tomography (CT) and colonoscopy confirmed edema in the gastrointestinal tract. Perforation of the jejunum was observed in a CT performed on the third day and an emergency operation was performed. Intraoperative findings showed severe edema of the jejunum and leakage of feces into the abdominal cavity. The patient was diagnosed with irAE enteritis comprehensively with severe wall thickening on CT and colonoscopy, negative stool culture, and pathological findings of CD8‐positive cells. Infliximab was administered before initiating steroids, to prevent reperforation. The enteritis improved by the 22nd day; however, CT performed on the 35th day of illness showed relapse of gastrointestinal wall thickening and G2 diarrhea symptoms; therefore, prednisolone (PSL) 60 mg/day was started on the 36th day of illness. After introducing PSL, enteritis did not reoccur, and the patient was discharged on the 63rd day of illness after admission. CONCLUSION: There are no reports of gastrointestinal perforation by atezolizumab/bevacizumab for hepatocellular carcinoma, and prior administration of infliximab. We therefore report the clinical course and management.