Nivolumab-induced tumour-like gastritis: A case report

Table 1 Case report timeline

Date	Event	Findings
December 2017	Chest CT	Tumour in the left lung (S1/2) with pleural metastases
January 2018	Fibrobronchoscopy with biopsy	Pathology report: poorly differentiated (G3) non-small lung cell adenocarcinoma, EGFR (-)
February - June	Chemotherapy treatment (Carboplatin, Paclitaxel, Bevacizumab), 6 courses
September	Chest CT	Reduction of target tumours by 16%. Stable oncologic disease
January 2019	Chest CT	Progression of the disease
January	Initiation of nivolumab treatment
December 2020	Beginning of gastrointestinal symptoms
February 2021	EGD with biopsy	EGD: Tumour-like endoscopic changes in the stomach; Histology: Chronic active (++) erosive gastritis with gland destruction and lymphoepithelial infiltration. Possible immune check-point inhibitor therapy-associated gastritis
March	Abdominal CT	Stomach changes related to chronic gastritis
March	EGD with biopsy	EGD: Progression of tumour-like endoscopic changes in the stomach; Histology: Chronic active (++) gastritis with erosions and intestinal metaplasia
March - April	First course of 20 mg/d of omeprazole
July	EGD with biopsy	EGD: Decreased diffuse inflammatory/infiltrative changes in the stomach wall; Histology: Chronic active gastritis (++) associated with immunotherapy
July - August	Second course of omeprazole 20 mg/d
September	COVID-19 infection; acute renal failure; cessation of nivolumab
October	Third course of omeprazole 20 mg/d
December	Chest CT	No progression of pulmonary disease
	Renal function improvement; Reintroduction of nivolumab
January 2022	EGD with biopsy	EGD: Gastric mucosa atrophy with focal intestinal metaplasia, gastric polyp; Histology: Hyperplastic gastric polyp
March	Acute renal failure; kidney biopsy; cessation of nivolumab	Histology: Insignificant and non-specific renal changes
May	Renal function improvement; Initiation of Atezolizumab treatment
October	Chest CT	No progression of pulmonary disease

CT: Computed tomography; EGD: Esophagogastroduodenoscopy; EGFR: Epidermal growth factor receptor.