Background: Trastuzumab + chemotherapy is considered the standard therapy for advanced human epidermal growth factor receptor 2 (HER2)-positive gastric cancer with mild manageable toxicity, on the basis of the results of a pivotal phase-III trial. Cerebrovascular events are not recognized as expected adverse effects of such therapy.
Case presentation: We report the case of a 67-year-old, current-smoking male with stage-IV HER2-positive gastric cancer who suffered right middle cerebral artery (MCA) embolism after trastuzumab + chemotherapy. He received trastuzumab and cisplatin on Day 1, followed by a continuous 5-fluorouracil infusion for 5 days as a first-line treatment. Four days after chemotherapy initiation, he presented with left hemiplegia, and brain magnetic resonance imaging and magnetic resonance angiography revealed a right MCA occlusion. No further chemotherapy was administered because of worsening performance status.
Conclusion: The present case, possibly the first such reported case, suggests the risk of development of embolism after trastuzumab + chemotherapy in HER2-positive advanced gastric cancer, although other factors should be considered.