Introduction:Though pediatric-onset systemic lupus erythematosus (SLE) is at high risk of coronary artery involvement, coronary artery dilation appears to be a rare characteristic of pediatric-onset SLE. In this article, we described 1 pediatric-onset SLE patient with coronary artery dilation at the diagnosis of SLE, in order to better diagnose and manage this cardiac complication of SLE in children.Patient concerns:A 13-year-old boy was admitted in hospital for daily fevers with the highest temperature of 39.2°C over 10 days, with rash, non-exudative conjunctivitis, cervical adenopathy, knee, and ankle arthralgi. The result of echocardiogram implicated coronary artery dilation and aortic regurgitation. Further laboratory tests showed: Coomb's test (+), decreased C3 complement. The results of immunologic tests were only to find ANA (+) with titer 1:3200, ds-DNA (+).Diagnosis:This patient was diagnosed as SLE complicated with coronary artery dilation.Interventions:The patient was treated with intravenous methylprednisolone pulse therapy. He was discharged home on prednisone maintain treatment.Outcomes:As soon as treatment, his temperature returned to normal, with recovery of rash, conjunctivitis, knee, and ankle arthralgi. However, the echocardiogram of this patient after 3 months also had dilation of left coronary artery (LCA) and right coronary artery (RCA).Conclusions: Cardiac complication can occur during the entire course of SLE, suggesting that routine echocardiogram surveillance may be necessary for all SLE patients to prevent morbidity and mortality from cardiovascular events.