Reversible Coronary Artery Aneurysm With Delayed Anti-inflammatory Therapy in Multisystem Inflammatory Syndrome in Children.

A 4-year-old boy with multisystem inflammatory syndrome in children before widespread recognition of this disease developed complications, including coronary artery aneurysm, without anti-inflammatory treatment. With delayed treatment, all sequelae resolved. This case demonstrates a natural history supporting the role of anti-inflammatory treatment even with delayed or equivocal diagnosis. (Level of Difficulty: Intermediate.).