Venous Calculi

VENOUS CALCULI, phlebolithon, are round, stone-like formations that sometimes occur in the lumen of certain veins, usually varicose veins (see Varicose veins). The basis of V. c. is a thrombus that formed in the vein, which subsequently dries out and becomes impregnated with lime salts, i.e., petrified, and later lies freely in the vein's lumen. The question regarding certain details of V. c. formation, and in particular, whether V. c. form as a result of petrification of a free, spherical venous thrombus or of a thrombus connected to the vessel wall through the process of organization and subsequently separating from the wall, is not yet fully clarified. In some V. c., bone formation is sometimes found. V. c. are most often encountered in the veins of the spleen, broad ligaments of women, in plexus prostaticus and pampiniformis; much less frequently in hepatic and pulmonary veins. V. c. do not cause any circulatory disorders.