Ruptured giant aneurysm of the left anterior descending coronary artery in Kawasaki disease.

This report describes Kawasaki disease (KD) in a rare autopsy case showing three uncommon phenomena: rapid aneurysmal development, ruptured giant aneurysm, and abscesses such as neutrophil aggregations, all contributing to the unpreventable sudden death of patients with KD. For a 5-year-old boy, KD was diagnosed on day 5 of his illness. His aneurysm was enlarged to a diameter of 18 mm on day 12, and the boy died on day 13. Aggregations of neutrophils containing myeloperoxidase and neutrophil elastase were scattered in chains over the aneurysmal wall of coronary artery, suggesting that destruction of the wall by an enzyme may have caused the rupture of the aneurysm.