Renal Primitive Neuroectodermal Tumor With Inferior Vena Cava Thrombus: Case Series and Literature Review of a Rare but Challenging Entity

Renal primitive neuroectodermal tumors with inferior vena cava (IVC) tumor thrombus is an extremely rare entity that poses a massive challenge to diagnosis and treatments. Histopathology remains the gold standard for definite diagnosis. Radical nephrectomy with NC tumor thrombectomy is a challenging procedure requiring vascular management techniques and experience. Adjuvant chemotherapy contributes to improved progression-free, but not overall, survival. Objective: To investigate the clinicopathological characteristics, treatments, and prognosis of patients with renal primitive neuroectodermal ectodermal tumors (rPNETs) with inferior vena cava (IVC) tumor thrombus. Patients and Methods: We retrospectively reviewed 6 patients with rPNETs and IVC tumor thrombus between January 2005 and December 2019, and identified 39 published cases through a literature review. The clinicopathological characteristics, treatments, and survival data were analyzed. Results: The median patient age patients was 26 years, and the male to female ratio was approximately 1:1. The average tumor diameter was 12.5 cm. Seventeen patients (37.8%) showed metastasis at diagnosis. Forty-three cases (95.6%) were managed with surgical resection, and 35 (77.8%) received adjuvant chemotherapy after surgery. Follow-up data were available for 41 patients (median follow-up, 10 months; range, 4.5-13.0). The median overall survival (OS) and median progression-free survival (PFS) were both 30.0 months. Patients who received adjuvant chemotherapy had better PFS than those who underwent surgery only (30.0 months [95% confidence interval [CI], 4.3-55.7] vs 5.0 months [95% CI, 1.0-9.0]; P = .036). In terms of OS, however, the difference between the 2 groups was not significant (30.0 months [95% CI, 8.4-52.6] vs 7.0 months [95% CI, 4.5-9.5]; P = .244). Conclusions: rPNET with IVCTT is an extremely rare entity that mostly occurs in young adults. Although multidisciplinary treatment is used, the prognosis of this disease remains unclear. RN with IVC tumor thrombectomy is a challenging procedure requiring vascular management techniques and experience. Adjuvant chemotherapy contributes to improved PFS, but not OS. Thus, early diagnosis and treatment play a key role in improving prognosis. (C) 2021 Elsevier Inc. All rights reserved.