Rev ChilRadiol 2016; 22(1): 39-46.Tumors that invade the inferior vena cava: An illustrativereview of the main imaging features on computedtomography and magnetic resonance*Matías Molina , Giancarlo Schiappacasse y Andrés LabraFacultad de Medicina, Universidad del Desarrollo-Clínica Alemana, Santiago, ChileAbstractThe objective of this article is to describe the multiple entities that can affect and invade the inferior venacava. Among these we can list not only benign entities,but with an aggressive behavior, but also malignancies that originate in organs adjacent to this vascularstructure or therein such as leiomyosarcoma. In thisreview different examples on computed tomographyand magnetic resonance with cases of angiomyolipoma, pheochromocytoma, adrenal carcinoma, renal cellcarcinoma, hepatocellular carcinoma, retroperitonealsarcoma and leiomyosarcoma originating in the inferiorvena cava, are presented. In addition, situations thatmay lead to misdiagnosis such as flow artifacts andpseudolipoma are presented.Keywords: CT, Inferior vena cava, Radiology, Tumors.IntroductionCurrently there is a significant increase in the acquisition of images for diagnostic purposes. The use ofcomputed tomography (CT) and magnetic resonanceimaging (MRI) are becoming more frequent and thusthe detection of abnormalities of the inferior vena cava(IVC) has become more common, so the radiologistshould be familiarized with the various entities that mayaffect it. The development of new imaging modalities hasmade it possible to improve the processes of detection,staging and monitoring of neoplasms originating in thesurrounding structures, as well as provide informationto clinical and surgical oncologists regarding the localand distant extension of the various types of abdominal tumors. For its part, the affection of the IVC maybe due basically to 2 types. The first corresponds toa tumoral thrombus occupying the vessel lumen andthe second to the invasion and infiltration as such ofthe vascular wall. This differentiation is essential whenmaking surgical decisions and defining the therapeuticalmanagement. Thus, the intraluminal extension of thetumor may be susceptible for complete resection andobtain healing results if other secondary locations orinvasion of adjacent organs is ruled out (1-3).This pictographic review aims to expose the mainentities that can invade or infiltrate this structure.Among these several of benign strain that can adopt anaggressive behavior and invade neighboring vascularstructures, including the IVC, and on the other hand,malignant neoplastic entities that spread through itvia endovascular areas or by direct local extension.In addition, we mention the various pseudo lesionsaffecting the IVC, the majority benign and which canlead to errors when interpreting the images.Renal angiomyolipomaThis is a rare tumor of mesenchymal origin, with astructure composed of vascular, smooth muscle andfatty elements. It presents sporadically or in associationwith tuberous sclerosis. By nature, the vast majority isbenign, however it can have an aggressive evolutioninvading the renal vein, IVC and even the right atrium(4,5)(Figures 1 and 2).Figure 1. Venous phase axial and coronal CT images.Shown here is a Lipomatosa strain lesion in the upper thirdof the left kidney, which invades the ipsilateral renal veinand inferior vena cava (arrow).Received 25th February 2016; accepted 26 th February 2016, Available on Internet 3 rd April 2016 2016 Published by Elsevier Spain, S.L.U. on behalf of SOCHRADI. This is an Open Access article under the CC BY-NC-NDlicense ).*Autor for correspondence. email address: [email protected] (M. Molina).39

Molina M, et al.Figure 2. Selective aortogram and arteriography of left renalartery is performed via the right femoral artery, with stenosisapproximately 1 cm distal to the ostium being visible. Thestenosis causes a reduction of 50% in the diameter of theartery and 75% of the area thereof.PheochromocytomaAnother tumor that can invade the IVC, both in itsmalignant and benign versions is the pheochromocytoma, which corresponds to a rare tumor composed ofchromaffin cells originating from neuroectodermal tissueof the adrenal medulla and which can be a producer ofcatecholamines. Traditionally these have been referredto as “the 10 percent” tumor, because this percentage isapplicable to various features. Thus, 10% are extra-adrenal,10% malignant and 10% are associated with particularsyndromes such as multiple endocrine neoplasia IIA andIII, Von Hippel Lindau syndrome and neurofibromatosis(6).Pheochromocytomas may present a locally aggressivebehaviour, invading structures such as the renal capsuleor the IVC (Figures 3 and 4).Rev ChilRadiol 2016; 22(1): 39-46.Some authors have reported that the invasion of the underlying venous structures can occur between 4-10%(8,9).This information, at the moment of issuing the report,is of fundamental importance because some groupshave reported that it affects patient survival and alsodetermines the surgical technique (Figures 5 and 6).In the particular case of renal cell carcinoma, invasionof the vena cava by tumor thrombus does not contraindicate surgical resection, with the possibility existing ofresecting the tumoral thrombus(3). On the other hand,it is important to confirm the extension of the thrombus,either infra or supradiaphragmatic, the latter being theworst prognosis, and also if the vascular wall is infiltrated,which involves resecting the vascular segment block,with the respective implications both in the immediatepostsurgical outcome as well as long term(3,9).Figure 4. MR imaging sequences T2 Fat-Sat and T1 respectively.A solid heterogeneous and hyperintense mass on T2-weightedsequence and isointense on T1 was identified, adjacent tothe vascular hilum of the right kidney (arrows), which invadesthe IVC lumen and which corresponds to an extra-adrenalpheochromocytoma.Figure 5. Venous phase CT coronal reconstructions. It featuresa large mass in the upper pole of the right kidney with invasionof the IVC extending to the right atrium compatible with renalcell carcinoma.Figure 3. Axial and coronal CT images pre and post-contrast(venous phase). Shown is a right adrenal solid tumor ofheterogeneous enhancement (arrows) and its invasion of theIVC determining also thrombosis of same toward flow (curvedarrows). Histopathological result shows a pheochromocytoma.Renal cell carcinomaThis corresponds to the most common kidney cancersubtype and represents about 2% of malignant cancersaffecting adults(7). Usually renal cell carcinoma (RCC)has an expansive growth and can invade or displacethe capsule. If its extension is deep, it can invade thepyelocaliceal system or the vessels of the renal hilum.40Figure 6. MR images in post-Gd T1, T2 FSE axial and coronalSSFP sequences. A heterogeneous mass that affects the upperhalf of the right kidney and invades the renal vein and the IVC,is shown. In the post-contrast sequence enhancement of theendoluminal mass is highlighted, which allows differentiationfrom a non tumoral thrombus. Alterations correspond to a renalcell carcinoma.

Rev ChilRadiol 2016; 22(1): 39-46.Figure 9. Axial and coronal CT images in venous phase,showing a liver mass affecting segments VII and VIII, ofheterogenous appearance and that invades the hepaticvein and the IVC, which corresponds to a hepatocellularcarcinoma (arrows).Figure 7. Phases of CT images without contrast, arterialand portal, where a mass composed of multiple solidnodules at the level of the right adrenal gland, that presentshypervascular behavior and invades the inferior vena cava(arrow), is observed.Adrenal carcinomaThis is a malignant neoplasm with a reportedprevalence of 0.5 - 2 cases per 1,000,000 patients.62% of patients have functional tumors that couldcause Cushing syndrome, virilization or feminization10(Figures 7 and 8).Hepatocellular carcinomaHepatocellular carcinoma usually invades the portalvenous system, but the invasion of the inferior venacava and the suprahepatics may occur in up to 4%of patients (11). The characteristic finding is the dilationof the veins involved and the presence of intraluminalthrombus that enhances after contrast administration.The presence of this type of condition predisposesto the development of distant metastases and worsens the prognosis, decreasing survival to only 1 to4 months12 (Figure 9). More so, for some authors,the invasion of the IVC is considered an exclusioncriterion for hepatocarcinoma surgical resection (13,14).Figure 8. Macroscopy of the sample that shows pearlywhitish coloured solid masses found in relation to the adrenalgland whose histopathology was consistent with a corticalcarcinoma with IVC invasion.Leiomyosarcoma of the inferior vena cavaLeiomyosarcoma is the primary malignant tumorthat most often affects the IVC, and it originates fromthe parietal muscle cells of the vessel. Approximately74% of leiomyosarcomas of the IVC affect womenbetween 40 and 60 years of age (15). This neoplasmmay depend on the lower middle or upper third of theIVC and have an intra or extraluminal component,featuring in two thirds of cases a predominantlyextraluminal growth, hindering the diagnosis of thisentity because it simulates a mass with its isocenterlocated in the retroperitoneum and which seems toinvade the IVC, when in fact it originates therein.This aspect is very important, since leiomyosarcomas arising in the IVC have a better prognosis withsurgery and complete resection of the vein, unlikewhat might happen with other tumors, in which onlyradio or chemotherapy could be offered (1). On CT itappears as a solid mass with calcifications and mayhave haemorrhagic or necrotic areas when it becomes bigger (Figure 10). On MR it may have a lowsign in T1-weighted sequences and intermediate orhigh sign in T2-weighted sequences, which dependmainly on the size of the necrotic component. Todetermine whether the lesion emerges from the IVC,the most frequent sign is the imperceptibility of thevenous structure as such, followed by the presenceof intraluminal tumor(16). In addition to having its originin the IVC, leiomyosarcoma can be of retroperitonealorigin and secondarily invade the vena cava, as setforth in Figure 11(2).Occasionally, other malignant entities such aspancreatic adenocarcinoma, Wilms tumor and metastasis in retroperitoneal lymph nodes may extendto the IVC. For example, in the case of the metastaticlymph nodes, some studies have shown that between3-11% of those derived from a non-seminoma typetesticular carcinoma could invade the IVC (17).Finally, it is important to note certain entities thatcan simulate lesions of the IVC and lead to errors,especially when associated with neoplasias, causingthe radiologist to overestimate a false intravascularaffection.41

Molina M, et al.Rev ChilRadiol 2016; 22(1): 39-46.Flow artifactsFlow artifacts are the most frequent entities thatcan simulate an IVC lesion, caused by the blendingof the contrasted venous blood from the renal veinswhen mixed with that which is not contrasted thatcomes from the lower extremities. It can also be seenin situations where low amounts of contrast are used,in cases of right heart failure and in patients wherethe acquisition sweep is performed at an early portalphase (Figure 13).Figure 10. Leiomyosarcoma of the IVC. Axial contrastenhanced CT image in venous phase. A large solidretroperitoneal predominantly hypodense mass, of heteroerogeneous enhancement and with calcifications (arrow)is identified. It presents mainly extraluminal growth, with alesser endoluminal component (curved arrow).Figure 13. Flow Artifact. Axial images with contrast in venousphase, where a hypodense endoluminal filling defect inthe IVC (open arrow) is observed, which disappears afterthe influx from the renal veins on homogenizing the dye(curved arrow).Figure 11. CT and PET/CT axial slices (hybrid positron emissiontomography and computed tomography image) and CT coronalreconstruction, where a poorly defined solid lesion located inthe retroperitoneal region situated in the interaortocaval space,which contacts and invades the IVC (straight arrow), is shown.The tumoral mass has important tracer uptake includingthe intraluminal component (curved arrow). In the coronalreconstruction it is possible to better visualize the invasion of theIVC. Biopsy gives proof of a high-grade retroperitoneal sarcoma.Venous thrombosisThe most common filling defect in the vena cavais thrombosis, which occurs most frequently in usersof oral contraceptives, patients with antiphospholipidsyndrome, vasculitis and various coagulopathies. Theuse of filters also determines the presence of endoluminal thrombus18. It is important to mention thatparaneoplastic hypercoagulable states can influencethe development of thrombi, which are difficult todifferentiate from tumor thrombus. One way to differentiate them is by identifying the intraluminal massenhancement after contrast administration.PseudolipomaThis is a rare pseudo-lesion in which the periarterialadipose tissue located on the caudate lobe appearsto extend into the IVC. The best way to determine ifit actually is real lesion or not, is by observing thecoronal or sagittal plane reconstructions (Figure 12).ConclusionThere are multiple entities that can affect the IVCand they represent a challenge for the current radiologist. This article describes a variety of diseases thatcan affect it. In all of them, the images allow adequateevaluation, thus contributing to decision-making.Conflict of interestsThe authors declare no conflict of interest.Bibliography1.2.Figure 12. Pseudolipoma of the IVC. CT axial image in venousphase, where, in the medial aspect of the IVC, a protrusion ofintraabdominal adipose tissue into the thorax generating the falseimpression of invasion of its lumen (red arrows), is observed.423.Mingoli A, Cavallaro A, Sapienza P, Di Marzo L, FeldhausRJ, Cavallari N. International registry of inferior venacava leiomyo- sarcoma: Analysis of a world series on218 patients. Anticancer Res. 1996; 16: 3201-3205.Hartman DS, Hayes WS, Choyke PL, Tibbetts GP.Leiom- yosarcoma of the retroperitoneum and inferiorvena cava: Radiologic-pathologic correlation. Radiographics. 1992; 12: 1203-1220.Vaidya A, Ciancio G, Soloway M. Surgical techniquesfor trea- ting a renal neoplasm invading the inferior

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Hepatocellular carcinoma usually invades the portal venous system, but the invasion of the inferior vena cava and the suprahepatics may occur in up to 4% of patients (11). The characteristic finding is the dilation of the veins involved and the presence of intraluminal thrombus that