Kawasaki disease is a disease of unknown etiology that most frequently affects infants and children under 5 years of age. Inflammation occurs in medium-sized muscular arteries throughout the body including the coronary artery, being classified as a systemic vasculitis syndrome. Histopathological investigations of Kawasaki disease have mainly focused on the coronary artery because it is directly associated with the cause of death. However, to identify the cause and pathology of Kawasaki disease, it is necessary to investigate lesions of whole organs. Thus, we attempted to review lesions in organs other than the heart and hypotheses of pathogenesis recently attracting attention.