[Clinical character of metanephric adenoma of the kidney: a case report].

To investigate the clinicopathological characteristics of metanephric adenoma (MA), we analyzed the clinical and pathological data of metanephric adenoma. A 39-year old woman with asymptomatic right kidney tumor for 4 years was admitted to the hospital. A tumor with the largest diameter of 28 mm in the right kidney was homogeneously enhanced on CT. The tumor was distinctly increased as compared with 4 years before. The diagnosis was right kidney tumor. Nephron-sparing surgery was given after general anaesthesia. And the relative literature was reviewed. The tumor was homogeneous, with integrity tegument, and a grey cutting surface. Histopathologically, the tumor cells formed an adenoid or papillary pattern and contained psammoma bodies. Immunohistologically, they were positive for AE1/AE3, vimentin and WT1, negative for CK7, EMA and RCC. Pathological diagnosis was metanephric adenoma. The follow-up data of 24 months were available and without recurrence. MA is peculiar. It is difficult to get the final diagnosis of MA only by imaging characters. 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 active surveillance is necessary.