Metanephric adenoma in a 59-year-old female: a case report.

We report a case of metanephric adenoma in a 59-year-old female. The tumor was incidentally detected on computed tomography (CT) and ultrasound (US), and diagnosed as left renal cell carcinoma by radiological examination. Left nephrectomy was performed. The tumor measuring 4 x 3 x 3 cm had a clear margin and was encapslated with thick fibrous tissue. The cut surface was yellow-white and the boundary of renal parenchyma was clear. Histopathologically, the tumor showed a characteristic composition of small uniform cells with regular nuclei that formed a tubular pattern. Immunohistologically, they were positive for Leu-7 and vimentin. Pathological diagnosis was metanephric adenoma. We discuss the radiological findings of metanephric adenoma.