Wilms Tumor with Vena Caval Intravascular Extension: A Surgical Perspective

Abstract

Wilms tumor (WT) is the most common kidney tumor in pediatric patients. Intravascular extension of WT above the level of the renal veins is a rare manifestation that complicates surgical management. Patients with intravascular extension are frequently asymptomatic at diagnosis, and tumor thrombus extension is usually diagnosed by imaging. Neoadjuvant chemotherapy is indicated for thrombus extension above the level of the hepatic veins and often leads to thrombus regression, obviating the need for cardiopulmonary bypass in cases of cardiac thrombus at diagnosis. In cases of tumor extension to the retrohepatic cava, neoadjuvant therapy is not strictly indicated, but it may facilitate the regression of tumor thrombi, making resection safer. Hepatic vascular isolation and cardiopulmonary bypass increase the risk of bleeding and other complications when utilized for tumor thrombectomy. Fortunately, WT patients with vena caval with or with intracardiac extension have similar overall and event-free survival when compared to patients with WT without intravascular extension when thrombectomy is successfully performed. Still, patients with metastatic disease at presentation or unfavorable histology suffer relatively poor outcomes. Dedicated pediatric surgical oncology and pediatric cardiothoracic surgery teams, in conjunction with multimodal therapy directed by a multidisciplinary team, are preferred for optimized outcomes in this patient population.

Keywords: Wilms tumor; inferior vena cava; nephroblastoma; pediatric cancer; pediatric surgery; vascular extension.

Figure 1

Diagram of Wilms tumor intravascular involvement classification system proposed by Abdullah et al. [11] wherein (1) indicates infrahepatic, (2) indicates retrohepatic, (3) indicates suprahepatic, (4) indicates right atrial, and (5) indicates right ventricular tumor thrombus extension. Created with BioRender.com.

Figure 2

A five-year-old female presented with a right-sided Wilms tumor (WT) with infrahepatic inferior vena cava (IVC) extension. She underwent neoadjuvant chemotherapy followed by nephrectomy, cavotomy, and thrombectomy. (A) Preoperative computed tomography (CT) demonstrating a right-sided WT with infrahepatic IVC thrombus (arrow) in the coronal plane and (B) sagittal plane. (C) Three-dimensional reconstruction of preoperative CT, showing the right-sided WT and intravascular thrombus (yellow) within the IVC (blue) and iliac veins, with adjacent aorta (red) and left kidney (brown). (D) Intraoperative photo with the patient’s head towards the top left, demonstrating the right-sided mass and vascular isolation with vessel loops around the right renal vein (bottom), infrarenal IVC (right), left renal vein (top right), and suprarenal IVC (top left) prior to cavotomy and thrombectomy. (E) Final surgical specimen, demonstrating vena cava thrombus (arrow) removed en bloc with the right kidney and tumor.

Figure 3

A 5-year-old female presented with a large right kidney mass with intravascular extension to the inferior vena cava (IVC) and right atrium (RA). She underwent neoadjuvant chemotherapy followed by local control surgery. Final pathology was reported as clear cell sarcoma of the kidney. (A) Preoperative computed tomography after neoadjuvant therapy demonstrating persistent right atrial thrombus (arrow) in the coronal plane. (B) Preoperative transthoracic echocardiogram with a heterogeneous, echogenic mass in the RA. (C) Intraoperative photograph after resection of right kidney and tumor, with the right renal vein obliterated by tumor and divided near its confluence with the IVC (yellow circle), a blue vessel loop around the infrarenal IVC (bottom), the liver reflected cephalad (top), and abdominal viscera reflected towards the patient’s left (right on photograph). (D) Delivery of a heterogeneous mass in forceps out of the right atrium after cardiopulmonary bypass initiation. (E) Piecemeal resection of tumor thrombus (yellow circle) during partial cavectomy (blue oval) of retrohepatic IVC, with the patient’s liver reflected cephalad (bottom left). (F) Following bovine pericardial patch repair of partial retrohepatic cavectomy (see the Supplementary Materials Video S2 for a video of intraoperative steps from this case).