Background: The surgical management of pediatric unilateral Wilms’ tumor (uWT) remains a subject of ongoing debate, particularly regarding the criteria for lymph node (LN) sampling. To address this, we implemented a modified radical nephrectomy (MRN) technique, incorporating ipsilateral perivascular lymph node dissection following nephrectomy to optimize the surgical approach. This study evaluates the safety and feasibility of MRN in the treatment of uWT. Methods: We retrospectively analysis of 105 uWT cases treated with MRN between January 2016 and June 2023. Clinical characteristics, treatment regimens, and patient outcomes were assessed. Results: All 105 patients underwent MRN successfully. Of these, 48 had upfront surgery, while 57 received neoadjuvant chemotherapy. Following nephrectomy, regional LN dissection was performed, with a median of 9 nodes removed. Lymph node metastasis was identified in 6 patients (5.7%). Tumor spillage occurred in 6 cases, predominantly during upfront surgery. Surgical complications were noted in 6 patients, all of which were managed conservatively. Recurrence was observed in 8 patients, including two local recurrences. The 3-year event-free survival and overall survival rates were 91.3% and 95.6%, respectively. Conclusion: The MRN technique demonstrated both safety and feasibility in the surgical treatment of pediatric uWT, with manageable postoperative complications. The findings suggest that MRN provides enhanced access for surgeons and facilitates more accurate staging, beyond the goal of simply removing the recommended number of LNs. This approach may improve both staging accuracy and long-term outcomes in pediatric uWT.

Background: Ultrasound-guided percutaneous core needle biopsy (PCNB) has been used more and more frequently in diagnostics of pediatric solid tumors in our center. It is less invasive than an incisional biopsy. However, reports relating to its reliability in clinical practice are limited. Therefore, we aim to investigate the reliability of this technique in the pediatric population. Methods: A 7-year retrospective study including patients ≤ 18 years who underwent ultrasound-guided PCNB in our center was conducted. Children who received PCNB and final surgical treatment were included. Their medical records were reviewed. Final surgical pathological diagnoses were used as the gold standard to assess the diagnostic efficiency of PCNB. Results: A total of 169 children were included in our analysis. 87.0% of patients underwent PCNB for abdominal and pelvic masses. 79.1% of biopsies were performed under local anesthesia. There were 141 malignancies and 28 benign lesions confirmed by surgery. The most common malignancy was neuroblastoma (73), and the most common benign condition was fibromatosis. The diagnostic yield was 94.1%. The success rate of PCNB in determining benign and malignant conditions was 94.3% (150/159). Consistency between PCNB and final diagnoses was found in 143 cases, giving a total accuracy of 89.9%. The accuracy for diagnosing malignancies was 96.8% (122/126), and for benign diseases 87.5% (21/24). The difference was not statistically significant (p=0.0818). Severe complications occurred in 6 patients (3.5%). No evidence of needle tract dissemination was found. Conclusions: Ultrasound-guided PCNB is safe and effective in diagnosing pediatric solid tumors, especially in malignancies.