Varicose veins are veins that have become enlarged. As an alternative to getting pumped efficiently throughout the veins, blood tends to pool in varicose veins, making them bulge out and seem gnarled. Blood clot. Sometimes a clot can kind inside of a hemorrhoid. This is known as a thrombosed hemorrhoid. https://www.sgvascularctr.com/varicose-vein-treatment-in-singapore-from-the-perspective-of-a-vascular-surgeon/