Metanephric Stromal Tumor of the Kidney in 9-year-old boy: Diagnostic Dilemma and Nephron-Sparing Approach

Metanephric stromal tumor (MST) is a rare benign renal neoplasm of childhood that must be distinguished from malignant pediatric renal tumors to prevent unnecessary chemotherapy. We report a 9-year-old boy who presented with epigastric pain and vomiting. Imaging revealed a 3.3 cm × 3.7 cm heterogeneous solid-cystic mass in the left kidney. Core biopsy suggested a benign mesenchymal lesion, and the patient underwent Type B nephron-sparing surgery (NSS). Histopathological examination confirmed MST. He remains asymptomatic and disease-free at 15-month follow-up. This case underscores the atypical older age of presentation and supports NSS as an effective management strategy.