Abstract
Introduction
True masses of the inferior vena cava (IVC) are uncommon and present a diagnostic challenge, even to experienced clinicians. IVC pathology spans a spectrum of primary neoplastic, secondary neoplastic, and non-neoplastic processes, including frequent pseudo-lesions posed by inconsistent delayed contrast imaging. As clinical presentation is often non-specific and symptom severity more dependent on mass location within the IVC than disease severity, the recognition of sometimes subtle imaging differences plays a key role in narrowing differentials, timely diagnosis, and appropriate treatment of patients. In this literature review, we will review how to approach imaging of IVC masses based on their location/features, discuss imaging techniques, and mass differentiation based on imaging features.
Main Body
Primary IVC masses are exceedingly rare in comparison to secondary involvement as part of caval extension or thrombus formation from neighboring abdominal malignancies. Additionally, non-neoplastic processes—including postsurgical changes in transplant patients, IVC stents, and fistula formation—are common mimics of neoplastic pathology. Differentiating these pathologies is critical, as definitive diagnosis of suspected neoplastic IVC masses often requires invasive tissue biopsies. Accurate diagnosis is contingent upon a proper understanding of IVC anatomy, selection of proper imaging modalities, and imaging characteristics of respective masses. Patient prognosis is often a function of mass location, where earlier mass effect and/or compressive symptoms can lead to earlier presentation to medical attention. Unfortunately, if a mass occurs in a location that does not produce more significant symptoms, identification may be largely incidental and risks worse outcomes. Imaging techniques can vary based on patient age, initial versus supplemental study, and level of concern for malignant processes. While ultrasound is often the initial modality employed, especially in children, contrast-enhanced computed tomography (CECT) generally serves as the most commonly utilized technique. Magnetic resonance imaging (MRI), especially magnetic resonance venography (MRV), offers superior reliability in the detection and delineation of tumor thrombus extent when compared with CT.
Multimodal imaging, including ultrasound with doppler, CECT, and MRI provide complimentary information regarding continuity with adjacent organs, vascular invasion, enhancement pattern, and possible metastatic activity to assist in distinguishing pathology. Important distinguishing characteristics for intraluminal IVC masses are an expansile appearance, positive “embedded sign,” and “imperceptible caval lumen sign.”
Conclusion
IVC masses are rare, with symptoms often dependent on their location, and require knowledge about their anatomical relationships, imaging features, and common presentations to accurately diagnose them. The utilization of multimodal imagining techniques enables clinicians to appropriately differentiate primary, secondary, and non-neoplastic masses, thus enabling accurate diagnosis and suitable therapeutic interventions.