Phleboliths tend to occur most often in one of the veins in the pelvis. These deposits are quite common, but they don't cause symptoms. You wouldn't know you had one unless it appeared on an x-ray, ultrasound, CT scan or MRI.
Pelvic phleboliths are usually small and round. The deposit may sit inside a vein that is very close to one of the ureters, the tubes that carry urine from the kidney to the bladder. On a plain x-ray, a phlebolith sometimes can look like a kidney stone.