[Renal adenoma treated with partial nephrectomy: a case report]

We report a case of renal adenoma which was diagnosed as renal cell carcinoma preoperatively. A 78-year-old man, who had been under observation for bladder cancer for 4 years, was incidentally found to have a small right renal tumor at follow-up computed tomography (CT). Enhanced CT demonstrated a tumor which was hypervascular, 10 x 10 mm size, at the lower pole of the right kidney. There was no evidence of distant metastasis. The preoperative diagnosis was renal cell carcinoma, cT1aN0M0, and we performed right partial nephrectomy. The histopathorogical finding was renal adenoma. Renal adenomas are benign tumors and not uncommon in autopsy cases. However, when they are detected clinically, it is difficult to distinguish them from renal cell carcinoma preoperatively.