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Phleboliths are small, round calcified thrombi found within venous channels. They are typically benign, asymptomatic, and often associated with vascular malformations, particularly venous hemangiomas or venous malformations.
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Key features
| Feature | Description |
|---|---|
| Definition | Calcified thrombus in a vein or venous malformation |
| Composition | Central fibrin core → layered deposition of calcium salts |
| Pathogenesis | Blood stasis → thrombosis → organization → dystrophic calcification |
| Condition | Notes |
|---|---|
| Venous malformations / Hemangiomas | Classic association; most common context |
| Maffucci syndrome | Soft-tissue hemangiomas with multiple phleboliths |
| Pelvic veins | Frequently seen in pelvic or prostatic venous plexus on X-ray |
| Klippel-Trénaunay syndrome | Capillary–venous–lymphatic malformations with overgrowth |
| Modality | Imaging features |
|---|---|
| XR | • Appearance: Small, round or oval calcifications, often with radiolucent center |
| • Location: Soft tissues (pelvis, thigh, neck, limbs) | |
| • Classic sign: "Target" or "bullseye" appearance (due to laminated calcification) | |
| • Multiplicity: May be single or multiple, clustered in venous malformations | |
| MR | • T1/T2: Signal voids due to dense calcification |
| • Gradient Echo (GRE)/SWI): Blooming artifact from susceptibility effects | |
| CT | • High-attenuation calcified foci |
| • Best for localizing deep or visceral phleboliths |
| Phlebolith | Other Entities | Key Differentiator |
|---|---|---|
| Round, lamellated calcification | Ureteral stones (pelvis) | Phleboliths medial to ureteral path, no colic symptoms |
| Central location in soft tissue | Myositis ossificans | MO has zonal calcification pattern (peripheral first) |
| Signal void with blooming | Foreign body or hemosiderin | Clinical history, no layering or venous connection |
| Clusters with venous lesions | Synovial chondromatosis (joint) | SC is intra-articular, phleboliths are extra-articular |