Pediatric Abdominal Malignancies and Intravascular Extension: Contemporary Single-Center Experience.

Introduction: Inferior vena cava (IVC) thrombus is an uncommon and challenging complication of abdominal malignancies in the pediatric population, which significantly influences the treatment options and clinical outcomes in this population.

Methods: In this review, we present the presentation, treatments, interventions, and outcomes with this clinically and technically challenging oncological finding from a free-standing children's hospital from 2006 to 2017.

Results: Fourteen patients with IVC thrombus were identified as having an associated abdominal malignancy. The abdominal malignancies consisted of eight Wilms tumors (63% stage III and 37% stage IV), and one spindle cell sarcoma, neuroblastoma (stage III), kidney clear cell sarcoma (stage III), sclerosing epithelioid fibrosarcoma, hepatoblastoma-epithelial (stage IV), and hepatic embryonal sarcoma (stage IV). 50% of patients were male, 71% White, 29% Black, 7% Hispanic; mean age at diagnosis was 4.09 (SD 2.43) years. CT imaging identified IVC tumor thrombus for 79% of patients, US abdomen complete recorded 14%, and MRI lumbar 7%. 3Out of 14 patients, 13 patients were taken to the operating room with 12 patients undergoing concurrent tumor resection and IVC thrombectomy. Of the remaining patients, one had IVC thrombectomy via femoral cutdown by interventional radiology, and one was noted to have resolution of IVC thrombus with neoadjuvant chemotherapy. Of patients who underwent resection, one required IVC ligation, and one patient required IVC interposition vein graft reconstruction using a right IJ conduit. 60% of patients undergoing thrombectomy received neoadjuvant chemotherapy. Mean time from the diagnosis of IVC tumor thrombus to surgical thrombectomy was 46 (SD 44) days. No operative mortalities were reported. There were five major complications (hemothorax, pulmonary embolisms, seroma, and sepsis) and two minor complications (pneumonia and UTI). With exclusion of patient who underwent IVC ligation, no patients developed signs of IVC compression or recurrent thrombosis after thrombectomy.

Conclusions: IVC tumor thrombus can significantly alter the clinical treatment, surgical options, and outcomes of malignant abdominal tumors. Treatment of IVC tumor thrombus included adjuvant chemotherapy, segmental IVC resection with or without reconstruction, thrombectomy with intimal stripping, or resection of the thrombus with part of the IVC wall. Evidence for standard treatment practices for IVC tumor thrombus in the setting of abdominal malignancy is lacking due to the rarity of this finding and the varied clinical presentations.