Tumors
Tumors can cause spider veins in a few ways. First, they may cause chronic venous hypertension. This can lead to the development of spider veins. Another way they can cause spider veins is by creating extrinsic compression, when a tumor presses on the surrounding tissues or blood vessels.
Extrinsic compression is associated with varicose veins and can lead to forming of small spider veins and larger ones. A third way tumors can cause spider veins is by causing extra compression. This happens when a tumor presses on the deep veins in the lower legs and feet, which causes blood to pool in the legs. These pooled blood cells then break down and leak out into the skin, forming spider veins.
