Objective: To explore the clinical, imaging and histopathological features of metanephric adenoma(MA). Methods: The reported MA was found 7 years after the resection of right duplex kidney and ureter. The resected tissue was analyzed by microscope and immunohistochemical stain, with literature review. Results: The tumor was located in renal parenchyma with clear border. Histologically, the tumor was composed of acinus, irregular tubules and papillary architectures lined by small embryonic cells. Also glomeruloid bodies were focally seen. The stroma was essentially acellular, and focally psammoma bodies were observed. Immunohistochemical study showed that the tumor cells were positive with Vimentin, CKpan, WT-1, and CD57, and negative with EMA, CK7, CD10, CD34, NSE and AMACR. The proliferative index of Ki-67 staining was less than 1%. No local recurrence and distant metastasis occurred during 40 months’ postoperative follow-up. Conclusion: The Clinical and imaging manifestations of MA is not typical, and the diagnosis should be based on histological features and immunohistochemical stain. Nephron-sparing surgery is eligible for the treatment of MA. Considering the uncertainty of the biological behavior and cellular origin of MA, a long-term follow up is necessary.