Wilms or non-Wilms tumors? Imaging features of renal tumors in pediatrics

Abstract

Introduction: Identifying the imaging features of renal tumors in pediatric population allows reaching more accurate diagnoses and implementing more appropriate treatments. Objective: To describe the imaging findings of renal tumors in children and to assess the association between imaging findings and histological diagnosis of Wilms tumors versus Non-Wilms tumors, and between imaging features and intraoperative rupture of Wilms tumors, as well as the level of agreement between radiological and histological diagnosis (Wilms vs. Non-Wilms tumor). Materials and methods: Cross-sectional study conducted in 47 children with a kidney tumor pathological diagnosis treated between 2012 and 2018 in a pediatric hospital in Bogotá, Colombia. The patients’ medical records, as well as their ultrasound, tomography and magnetic resonance studies were reviewed. Two univariate logistic regression analyses were performed to assess the association between imaging findings and histopathological diagnosis and between imaging features and intraoperative rupture of Wilms tumors, calculating the respective Odds Ratio (OR) with a 95% confidence interval. In addition, the level of agreement between radiological and histological diagnosis was determined using the Kappa coefficient. Results: A significant association was found between histological diagnosis of Wilms tumor and the presence of necrosis, tumor enhancement, pseudocapsule, rupture signs, tumor volume and tumor size (OR: 21.6, 15.17, 14.57, 8.21, 7.93 and 4.37, respectively; p<0.05). An association between having Wilms tumor and lower frequency of metastases was also found (OR: 0.19; p<0.05). The Kappa coefficient between radiological diagnosis of Wilms/non-Wilms tumors and histological findings was 0.78 (95%CI: 0.59-0.96; p<0.05). Additionally, Wilms tumors volume was significantly associated with the occurrence of rupture (OR: 3.08; p<0.05). Conclusions: There are imaging findings such as necrosis, tumor enhancement and tumor volume that can help predict the histological diagnosis and intraoperative rupture risk of Wilms tumors.