A thirty-eight-year-old man with primary thrombocythemia, von Recklinghausen neurofibromatosis, and myocardial-infarction-related left ventricular aneurysm with spontaneous echocardiographic contrast was followed up, suggesting that: 1. Neurofibromatosis may promote silent myocardial infarction or ischemia. Whether involvement of cardiac sensory nerves is a possible underlying mechanism remains nevertheless uncertain. 2. Platelets, whose role in the genesis of spontaneous echocardiographic contrast has been advocated, are probably not involved in this phenomenon, even in large numbers.