Conclusion
The case we encountered is extremely rare in four respects: ACS occurred immediately after vaccination, the collected thrombus was evaluated pathologically, it showed large vasa vasorum, and the unknown aetiology of COVID-19 vaccine-related ACS was partly clarified. Careful observation after vaccination is necessary for those at high risk of cardiovascular diseases, and intravascular imaging and pathological examination of the thrombus are effective for evaluating coronary lesions and clarifying the pathogenesis of ACS.