Misdiagnosis of severe and atypical oxaliplatin‑related hypersensitivity reaction following chemotherapy combined with PD‑1 inhibitor: A case report and literature review.

Although the efficacy of treatment strategies for cancer have been improving steadily over the past decade, the adverse event profile following such treatments has also become increasingly complex. The present report described the case of a 67-year-old male patient with gastric stump carcinoma with liver invasion. The patient was treated with oxaliplatin and capecitabine (CAPEOX regimen) chemotherapy, combined with the programmed cell death protein-1 (PD-1) inhibitor tislelizumab. Following treatment, the patient suffered from chills, high fever and facial flushing, followed by shock. Relevant examination results revealed severe multiple organ damage, as well as a significant elevation in IL-6 and procalcitonin (PCT) levels. Initially, the patient was diagnosed with either immune-related adverse events (irAEs) associated with cytokine release syndrome caused by tislelizumab or severe bacterial infection. However, when tislelizumab treatment was stopped and the CAPEOX chemotherapy regimen was reapplied, similar symptoms recurred. Following screening, it was finally determined that severe hypersensitivity reaction (HSR) caused by oxaliplatin was the cause underlying these symptoms. A literature review was then performed, which found that severe oxaliplatin-related HSR is rare, rendering the present case atypical. The present case exhibited no common HSR symptoms, such as cutaneous and respiratory symptoms. However, the patient suffered from serious multiple organ damage, which was misdiagnosed as irAE when oxaliplatin chemotherapy combined with the PD-1 inhibitor was administered. In addition, this apparent severe oxaliplatin-related HSR caused a significant increase in PCT levels, which was misdiagnosed as severe bacterial infection and prevented the use of glucocorticoids. This, in turn, aggravated the damage in this patient.