Venous malformations of the heart.

So-called varicosities of the fossa ovalis are rare, venous malformations, which have also been previously labeled angiomas. In four cases encountered as incidental autopsy findings, the microscopic appearance was that of dilated venous channels. Veins larger than 100 micrometer in diameter were found close to the posteroinferior rim of the fossa ovalis in 18 of 21 consecutive, routine autopsy cases. The pathogenesis of the venous dilation is unknown but it may be related to the development of the interatrial septim. The term venous malformation seems preferable to varix for such lesions.