Immune checkpoint inhibitor-related intestinal pseudo-obstruction and multisystem immune-related adverse events in a post-gastrectomy patient: a case report and literature review.

BACKGROUND: Immune checkpoint inhibitors are increasingly recognized to be associated with multisystem immune-related adverse events. Cases presenting predominantly with intestinal pseudo-obstruction (IPO) are rare, prone to misdiagnosis, and may indicate broader immune-mediated toxicity. CASE PRESENTATION: We report the case of a patient with gastric cancer who developed intestinal pseudo-obstruction and multisystem immune toxicity during postoperative adjuvant chemotherapy plus nivolumab. The patient's symptoms improved rapidly after glucocorticoid treatment. CONCLUSION: Immune checkpoint inhibitor-related intestinal pseudo-obstruction (irIPO) should be recognized early and diagnosed on the basis of a comprehensive clinical assessment. Differential diagnosis, multidisciplinary collaboration, and active screening for additional organ involvement are essential. Early glucocorticoid treatment may improve clinical outcomes.