Pelvic Phleboliths – What are Phleboliths in the Pelvis?

Blausen_0053_Artery_NormalvsDiseasedVessel (1)Pelvic phlebolitbs are calcified thrombi within the veins, and show up as small round stones in pelvic x-rays. Their formation has been linked to a deficiency of dietary fibre, together with an increase in clotting tendency, and they have been detected in up to 66% of the American population. They are generally considered to be harmless growths that range in size from minute specks to growths of half an inch in diameter.

The medical-dictionary definition of phleboliths is: Masses, deposits or growths which develop in the wall of a vein and are composed of calcium or lime. Common in the pelvic area and are stationary and harmless but can indicate the presence of more dangerous conditions or diseases. A calcification of an old thrombus, also called vein stones.

Pelvic phleboliths are very common. They cause no pain by themselves, usually being a clinical finding apart from the symptoms that prompt the original examination.

Although it is harmless on its own, pelvic stones can be warning signs of conditions such as:

  • Benign tumors in young patients
  • Colon hemangiomas
  • Colon distention
  • Dilated bladder
  • Or various tumors or cancers


Why do phleboliths form in the pelvic veins when they are rare elsewhere in the body? In adults, pelvic veins are valveless and poorly supported in loose conrective tissue. It has been proposed that sudden, intermitent increases in abdominal pressure, such as when straining during defecation, can serve to damage the vessel wall and thereby predispose to phleboliths and thrombosis.

In other words, the consumption of a low-fiber diet can cause phleboliths to develop. In countries in which residents eat less cellulose-laden foods, this leads to the precipitaton of phleboliths, to the promnsity for colonic diverticula whose formation is caused by straining at stools, prolonged colonic transit time, to large intestinal polyps and colonic malignancies.

In addition, as the age increases, phlebolith formation becomes quite common. Although it may not be impossible, trauma relationships and surgical complications are unlikely to occur.

Calcification normally occurs with aging in certain tissues. For example the costochondral joints which are the cartilage joints between the sternum (breast bone) and our ribs undergo calcification with age and appear dense white in X-rays.

The 6 Types of Phleboliths



  1. Liquid-filled: Phlebolith cysts can be filled with liquid (cortical) meaning that there are other types of packing, such as proteins and the like.
  2. Venous: Phleboliths within a venous malformation may be mistaken for a salivary stone given the similar calcified nature and location.
  3. Oxalate: The most common type of stone in the US is calcium oxalate which happens to be the most radio-opaque type.
  4. Phosphate: Almost always phleboliths’ opacity is due to the accumulation of calcium carbonate, with lesser contributions made by ammonium phosphate and magnesium ammonium phosphate.
  5. Bilateral: Stone protocol CT (done without IV or oral contrast so as to not obscure finding a stone) may show bilateral pelvic calculi.
  6. Cancerous: Or very rarely cancerous. Usually the doctor only confirms that the cyst size of the film exam (ultrasound or CT scan) is not too big.

If it is too large, it may damage surrounding cells and cause problems. If the growth swells too large, the doctor will surgically remove a part of the cyst wall and drain it, in order to confirm the nature of this low density lesion in the pelvis. This will ensure the calcium deposit is a harmless cyst, not a tumor etc.

It is necessary to obtain specific information from the doctor. Those with high density such as bones look white with X-rays. Of course, the dyes look white. You may not recognize subtle differences in various shadows unless you are accustomed to reading X-rays.

Phleboliths Vs. Kidney Stones

When dealing with kidney stones, it is important to delineate between a pelvic phlebolith and a stone. Your CAT scan should show the dye filling the ureter and the phlebolith outside the ureter, or your doctor would have done other testing. If your CAT scan was normal, showing prompt excretion of contrast and normal function, you should not have anything to worry about. If you have pain or another reason to suspect that your kidney is blocked, a non-contrast CT scan can be done to look for a stone vs. a phlebolith.

On radiographs of the abdomen and pelvis, phleboliths often have a characteristic radiolucent center that helps to distinguish them from ureteral stones.

Calcium Deposits


What radiologists generally call mineralization is the area of calcium deposition where white opacity resembles the density of the bone found in x-rays. Calcium deposition in tissues can be both normal and abnormal.

A common cause of local calcification in the pelvic region is “Phelboliths”. Calcite is mineralization and occasionally occurs in small pelvic veins after coagulation. These are usually multiple and are found mainly in the pelvic region of the barium enema test.

There are many other causes of mineralization, such as tumors (both benign and malignant) and other common causes of hypercalcemia (increase in calcium in the blood).

Should I Worry?

Pelvic phleboliths are very common in the lower veins of the pelvis and are not clinically significant. In other words, don’t be worried, as they are commonly seen in ordinary healthy people. When located in the pelvis it is sometimes difficult to distinguish from kidney stones in the ureter on X-rays.