Metanephric adenoma of the kidney.

Metanephric adenoma is a morphologically distinct renal tumor that appears histologically benign and whose epithelial component is predominant. We report a case of metanephric adenoma in a 42-year-old woman. The tumor was composed of immature epithelial cells forming tubules with abortive glomeruloid structures. The bland appearance of the cells forming this tumor were in accordance with the apparently benign postnephrectomy clinical course.