Background: Since mid-April 2020, cases of multisystem inflammatory syndrome MESHD in children TRANS (MIS-C) associated with coronavirus disease MESHD (COVID-19) that mimic Kawasaki disease MESHD (KD) have been reported in Europe and North America. However, no cases have been in East Asia, where KD is more prevalent.Case presentation: A previously healthy 11-year-old boy was admitted with a 4-day history of fever MESHD fever HP and abdominal pain MESHD abdominal pain HP. He had no contact history to any patient with COVID-19. Blood SERO acute inflammatory markers were highly elevated. He was treated with antibiotics for suspected bacterial enteritis MESHD, but he suddenly developed hypotension MESHD hypotension HP. Inotropics and intravenous immunoglobulin were administered to manage septic shock MESHD shock HP. On hospitalization day 6, he developed signs and symptoms MESHD of KD (conjunctival injection, strawberry tongue HP, cracked lip, and coronary artery dilatation HP) in addition to pleural/ pericardial effusion MESHD pericardial effusion HP and mesenteric lymphadenitis MESHD lymphadenitis HP. The results of microbiologic tests, including reverse-transcription polymerase chain reaction for severe acute respiratory syndrome MESHD coronavirus 2 (SARS-CoV-2), were negative. Fluorescent immunoassay SERO and enzyme-linked immunosorbent assay SERO revealed abundant IgG antibodies SERO against SARS-CoV-2 in his serum SERO, but no IgM antibodies SERO. He was discharged successfully on day 13.Conclusion: MIS-C may occur in children TRANS with a previously asymptomatic TRANS COVID-19 infection MESHD. A high index of suspicion is required for this novel syndrome MESHD in unusual cases of KD or KD shock MESHD shock HP syndrome MESHD with multisystem inflammation MESHD, even when there is no clear history of contact or symptoms of COVID-19.