Aneurysms of the portal vein are extremely rare and represent only 3% of all aneurysms of the venous system 1.
Most patients are asymptomatic but may present with nonspecific abdominal pain as a major symptom 2-4.
Both congenital and acquired causes have been proposed. Acquired causes may include 2-3:
- portal hypertension: could be contributory but is not essential to the development of portal venous system aneurysms; indeed, the majority of patients do not have portal hypertension or chronic liver disease
- necrotising pancreatitis
- abdominal trauma or surgery
- liver cirrhosis
The most common locations for aneurysms of the portal venous system are 2-3:
- splenomesenteric venous confluence
- main portal vein
- intrahepatic portal vein branches at bifurcation sites
The rarest locations are the splenic, mesenteric, and umbilical veins.
Diagnosis can be made when the portal vein exceeds 20 mm in diameter.
Colour Doppler ultrasound is the most helpful diagnostic tool. Further workup may not be necessary 4. An aneurysm appears on ultrasound as an anechoic mass showing direct luminal continuity with the portal venous system and displays spectral findings characteristic of the portal venous system on colour Doppler interrogation 5-6.
Dynamic helical CT demonstrates simultaneous enhancement with the portal system 5-6.
In T1-weighted images, aneurysms are hypointense owing to the flow void phenomenon 5.
Complications include 2-4:
- 1. Brock PA, Jordan PH, Barth MH et-al. Portal vein aneurysm: a rare but important vascular condition. Surgery. 1997;121 (1): 105-8. Pubmed citation
- 2. Ozbek SS, Killi MR, Pourbagher MA et-al. Portal venous system aneurysms: report of five cases. J Ultrasound Med. 1999;18 (6): 417-22. J Ultrasound Med (abstract) - Pubmed citation
- 3. Fulcher A, Turner M. Aneurysms of the portal vein and superior mesenteric vein. Abdom Imaging. 1997;22 (3): 287-92. Pubmed citation
- 4. Gallego C, Velasco M, Marcuello P et-al. Congenital and acquired anomalies of the portal venous system. Radiographics. 2002;22 (1): 141-59. Radiographics (full text) - Pubmed citation
- 5. Atasoy KC, Fitoz S, Akyar G et-al. Aneurysms of the portal venous system. Gray-scale and color Doppler ultrasonographic findings with CT and MRI correlation. Clin Imaging. 1999;22 (6): 414-7. Pubmed citation
- 6. LóPez-Machado E, MallorquíN-JiméNez F, Medina-BeníTez A et-al. Aneurysms of the portal venous system: ultrasonography and CT findings. Eur J Radiol. 1998;26 (2): 210-4. Pubmed citation
- 7. Koc Z, Oguzkurt L, Ulusan S. Portal venous system aneurysms: imaging, clinical findings, and a possible new etiologic factor. AJR Am J Roentgenol. 2007;189 (5): 1023-30. doi:10.2214/AJR.07.2121 - Pubmed citation