From the Research
Pelvic phleboliths are small, calcified nodules that form within the veins of the pelvis and are almost always benign, requiring no treatment. They develop when blood clots in the pelvic veins calcify over time, essentially becoming small stones within the vein. Phleboliths are typically round or oval in shape, measuring 2-5 mm in diameter, and appear as small, dense spots on X-rays, CT scans, or other imaging studies. They are extremely common findings, especially in adults over 40, and generally increase in frequency with age, with a reported prevalence of 38.9%-48% in adults 1.
Characteristics of Pelvic Phleboliths
- They are composed of calcified laminated fibrous tissue, with a surface layer continuous with vein endothelium 1.
- They may be associated with diverticulitis, vascular abnormalities, and are more commonly seen in individuals from economically developed countries 1.
- Radiological signs suggestive of phleboliths include the presence of central lucency, rounded shape, and the comet-tail sign 1.
- Phleboliths appear to have a significantly lower Hounsfield unit enhancement than ureteral calculi (160-350 HU) 1.
Diagnosis and Differentiation
- The soft-tissue "rim" sign and a geometric shape are radiological signs predictive of ureteral calculi on unenhanced CT scanning, helping to differentiate them from phleboliths 1.
- While they may sometimes be confused with other conditions like kidney stones or calcified lymph nodes on imaging, radiologists can usually distinguish phleboliths by their characteristic appearance and location within the pelvis.
Clinical Significance
- Pelvic phleboliths are generally considered harmless and do not require treatment 2.
- They rarely cause symptoms and are usually discovered incidentally during imaging performed for other reasons.
- The formation of phleboliths is related to slow blood flow in the pelvic veins, which can lead to small clots that eventually calcify.
- Given their frequency and the potential for diagnostic confusion with more serious conditions like ureteral calculi, it's crucial for clinicians to be aware of their characteristics and how to differentiate them accurately 1.