Pelvic Phleboliths: Management
Pelvic phleboliths require no treatment as they are benign, asymptomatic calcifications within pelvic veins that have no clinical significance and pose no health risk. 1
What Are Pelvic Phleboliths?
Pelvic phleboliths are focal calcifications that develop within pelvic veins, composed of calcified laminated fibrous tissue with a surface layer continuous with vein endothelium. 1 They are extremely common, occurring in 38.9%-48% of adults, with prevalence increasing in individuals over age 40 and affecting both genders equally. 1
Clinical Significance
Phleboliths are clinically benign and do not require any intervention, monitoring, or treatment. 1 While historically two case reports suggested an association with thrombosis 2, this is exceedingly rare and phleboliths are generally considered harmless. 2
The primary clinical relevance of phleboliths is diagnostic confusion with ureteral calculi when evaluating patients with suspected kidney stones. 1, 3 This is a radiological challenge, not a treatment issue.
Distinguishing Phleboliths from Ureteral Stones
When phleboliths are identified on imaging, the key clinical task is differentiating them from ureteral calculi in patients presenting with flank pain or hematuria:
On CT Imaging:
- Central lucency is seen in 8%-60% of phleboliths with 100% specificity for phleboliths (though sensitivity varies by slice thickness). 1, 3
- Rounded/geometric shape has 91% positive predictive value for phleboliths versus 100% PPV for geometric shape predicting ureteral stones. 1
- Comet-tail sign has 21%-65% sensitivity and 100% specificity for phleboliths. 1
- Lower Hounsfield units (160-350 HU) compared to ureteral calculi. 1
- Thin-slice CT (1-mm collimation) reveals central lucency in 60% of phleboliths with 100% specificity and round contour in 97% with 93% specificity. 3
On Plain Radiographs:
- Central lucency is visible in approximately 63% of phleboliths on plain films. 4
- Multiple phleboliths are often present near the ureters. 5
Common Diagnostic Pitfall
The most important pitfall is mistaking phleboliths for intraperitoneal or malpositioned intrauterine devices (IUDs) when IUD strings are missing. 5 In such cases, three-dimensional ultrasonography and CT pelvis can definitively distinguish phleboliths from displaced IUDs. 5
Management Algorithm
- Incidental finding on imaging: No action required. 1
- Suspected ureteral calculus: Use radiological features above to differentiate; if uncertain, thin-slice CT with bone algorithm provides definitive characterization. 3
- Suspected IUD malposition: Obtain 3D ultrasound and/or CT pelvis to distinguish from phleboliths. 5
- No follow-up imaging needed once phleboliths are confirmed. 1