Metanephric Adenoma : Introduction

Comments:
Introduction: Metanephric adenoma is a rare benign renal neoplasm composed of small primitive-appearing tubules and acini composed of embryonal epithelial cells. It belongs to the family of metanephric tumors that include metanephric stromal tumor (a pure stromal neoplasm mostly seen in pediatric patients) and metanephric adenofibroma (mixed epithelial and stromal neoplasm). The tumor resembles epithelial-predominant nephroblastoma and solid variant of papillary renal cell carcinoma.

Despite morphologic resemblance and immunoreactivity for WT1, metanephric adenomas are genetically distinct from Wilms tumor and do not show allelic changes at 11p13 region. In contrast, 90% of metanephric adenomas have BRAF V600E mutations that are not seen in Wilms tumor.