Unilateral iliac vein occlusion, caused by bladder enlargement, simulating deep venous thrombosis.

A variety of conditions cause unilateral leg swelling and thus mimic deep venous thrombosis (DVT). A heretofore-underappreciated condition that may lead to unilateral iliac vein compression, simulating DVT, is massive enlargement of the bladder caused by urinary retention. A case that demonstrates this condition is described. Although this disorder has been reported only three times before, its occurrence should be recognized by clinicians in light of the overall aging of our society. In addition, this case highlights the need for careful and thorough evaluation of patients who have unilateral lower-extremity edema.