Simultaneous diagnosis of a metanephric adenoma and a clear cell carcinoma of the contralateral kidney

Metanephric adenoma of the kidney is a rare, newly recognized entity of a unique benign renal tumor. Clinically, pain, hematuria and palpable mass are the most common presenting signs. Females predominate by well over 2:1. A higher incidence of polycythemia is often found in these patients. Only a few cases of this type of adenoma have been reported in the literature. We report on a 78-year-old female patient with a metanephric adenoma of the left kidney, which showed typical clinical, radiologic, microscopic and immunohistochemical findings. A clear cell carcinoma of the contralateral kidney was also discovered and treated.