An unusual case of fatal myocardial infarction in a neonate due to coronary arteries is compared with two lethal cases of Mucocutaneous Lymph Node Syndrome and/or Infantile Periarteritis Nodosa (MLNS/IPN). The neonatal coronary arteritis was pathologically indistinguishable from typical forms of MLNS/IPN, which cannot be reliably separated and whose strange epidemiologic features as well as their etiology(-ies) remain to be clarified. It is suggested that further research of the etiology of MLNS/IPN should be aware of a possible neonatal variant of this syndrome.