Conclusions: MIS-C could be suspected even when clinical data and performed tests suggest acute appendicitis especially when at least three out of four signs are present: CRP > 55.8 mg, symptoms last 3 days or longer, febrile fever is present, and any kind of other system involvement is noticed, especially with a known prior recent COVID-19 contact, infection or a positive COVID-19 antibody IgG test. Here, CRP is linked to infection.