Patients who often present with unilateral leg swelling without other symptoms may have an underlying anatomical condition in which the large pelvic artery compresses the pelvic vein next to it.  This causes a compressive effect in which the vein does not sufficiently drain the leg of blood.  This force can increase the risk of a Deep Vein Thrombosis (DVT), the complete or partial blockage of veins due to a blood clot.  This condition can be difficult to detect, with most cases being diagnosed along with DVT. While some patients are asymptomatic, others can experience multiple symptoms in their legs including swelling, pain, tenderness, redness or discoloration of the leg, enlarged veins, legs size discrepancy, ankle skin discoloration or ulcers and development of varicose veins in the pelvic area.  This condition often leads to venography to confirm the diagnosis and concurrent treatment.