Metanephric adenoma treated with laparoscopic radical nephrectomy

Metanephric adenoma is rare renal adenoma. In some cases, it is difficult to distinguish from other renal neoplasms such as Wilms' tumor or renal cell carcinoma on the basis of clinical and histologic findings. A unique case of metanephric adenoma of left kidney is reported in 35-year-old foreign woman presenting with intermittent left flank pain for 3 months. Computed tomography revealed a heterogeneous enhanced mass, 7.5× 6.8cm in diameter, at the lower pole of the left kidney. Laparoscopic radical nephrectomy was performed under the clinical impression of hypovascular renal cell carcinoma or oncocytoma. The resected mass, measuring 8×7cm, was well circumscribed and its cut surface was tan-pink. Microscopically, the tumor cells had small scant cytoplasms, containing round and uniform nuclei. There was no mitosis or cellular atypia indicating a malignant transformation. The histological diagnosis was metanephric adenoma. The patient was healthy without recurrence or metastasis 6 months after surgery.