Two cases of unexpected sudden death due to cystic medionecrosis of the aorta associated with bloodless aortic dissection.

The autopsy findings from two rare cases of sudden death concerning a 31- and a 44-year-old woman are reported. Autopsy and morphological examination revealed a dissection of the aorta but no rupture into the pericardial sac. In both cases mucoid deposits in all layers of the media and rarefication of the elastic fibers were found, rendering cystic medionecrosis as the cause of the aortic dissection. In these unusual cases, only a very small intimal tear was present, but no blood in the dissected aortic wall. Evidence of left ventricular hypertrophy and a history of hypertension were reported in both cases. No extension of the aortic dissections into the left or right coronary artery and no other clinical or pathological findings associated with aortic dissection were present. Cystic medionecrosis was the cause of the aortic dissection in these cases. The mechanism of death in both cases is discussed.