Double renal cell carcinoma with histological type of clear cell carcinoma and papillary carcinoma in the same kidney concurrently treated with robot-assisted partial nephrectomy.

Introduction: The presence of two different histologic types of renal cell carcinoma in the same kidney is rare in clinical practice. This report describes a patient with ipsilateral renal cell carcinomas, consisting of a clear cell renal cell carcinoma and a papillary type 1 renal cell carcinoma, who was successfully treated by robot-assisted partial nephrectomy.

Case Presentation: A 70-year man was referred to our hospital for the treatment of two right mid-pole renal tumors, measuring 51 mm and 31 mm in diameter. The two tumors, which differed in contrast enhancement on computed tomography, were removed simultaneously by robot-assisted partial nephrectomy. Histopathological and immunohistochemical findings confirmed that one tumor was a clear cell renal cell carcinoma, pT1a, and the other was a papillary type1 renal cell carcinoma, pT1b.

Conclusion: This report describes a rare patient presenting with two ipsilateral renal cell carcinomas differing in histology. Robot-assisted partial nephrectomy was the safe and effective nephron-sparing surgery, even in patients with complex double renal tumors.