Reply

We appreciate Dr Kurtcehajic and colleagues’¹ interest in our retrospective study on the natural history of portal venous system aneurysms.² The primary goal of our manuscript was to begin to understand factors associated with growth, stability, and regression of this rare visceral venous pathology. As highlighted by our colleagues, this is an emerging area of interest, with management primarily founded on expert opinion.

We agree that distinguishing the morphology of portal aneurysm is important as it will help define the behavior of the subgroup over time. Unfortunately, the morphology of venous aneurysms across all locations, including the portal venous system, is understudied. In a review of 38 portal vein aneurysms (PVAs), one saccular PVA (2.6%) was reported, with no specific complications related to morphology.³ Outside of the portal venous system, a review of peripheral venous aneurysms found saccular morphology associated with thromboembolism and fusiform with higher thrombus burden,⁴ which raises an interesting question for future study with a sufficient cohort of saccular PVAs available for analysis.

Our analysis was largely based on available computed tomography (CT) imaging for each patient and unfortunately did not allow for comparison of different imaging modalities. Given the increased utilization of CT scans in the United States, PVAs are increasingly identified as incidental findings, which allowed us to compare a larger cohort of aneurysms. However, as this study was retrospective, the follow-up intervals varied for each patient and did not have three imaging modalities available for comparison at each time point. Our colleagues raise an important question regarding the best imaging modality for the diagnosis and surveillance of PVAs. Both ultrasound and CT are commonly utilized due to widespread availability and accuracy, whereas magnetic resonance imaging is used less due to the cost and time the test requires.^3,5,6 The Doppler ultrasound study can confirm the vascular nature of the lesion by confirming monophasic venous flow pattern.^5,6 The portal venous phase of CT angiography provides detailed multi-planar views of the entire portal venous system, which is beneficial for differential diagnosis and assessment of complications such as thrombosis, compression of adjacent organs, or rupture. However, ultrasound may be the best imaging modality for long-term surveillance, given absence of radiation and accessibility of ultrasounds in general.

We intentionally described PVAs as idiopathic to refer to PVAs with no identifiable cause, rather than congenital, as we had no radiographic evidence from infancy or childhood to confirm congenital etiology, which may result in misleading classification. Furthermore, we excluded children under 18 years old from our analysis with plans for future study. However, it is likely that some of the idiopathic PVAs in the absence of known morbidities or abdominal trauma are of congenital etiology. Congenital etiology is supported by the presence of PVA on fetal ultrasound⁷ and may partly arise from the diverticular remnant formed from incomplete involution of the right primitive vitelline vein.⁸

We thank Dr Kurtcehajic and colleagues for their shared interest on this rare pathology and exciting areas for future direction.