A 16-year-old boy had toxic shock syndrome (TSS); Staphylococcus aureus bacteremia developed 11 hours prior to his death, which was three days after onset of the illness. The isoelectric focusing pattern of the staphylococcal isolate differed from both non-TSS and classic TSS S aureus isolates. Anatomic findings suggest three pathogenetic mechanisms: (1) immune complex-associated pulmonary microangiitis and vasculitis in the skin and skeletal muscle; (2) parenchymal cell "microvesicular" fatty metamorphosis in the liver, myocardium, renal tubules, and pancreas, and (3) pancarditis.