Incidence of benign pathologic lesions at partial nephrectomy for presumed RCC renal masses: Japanese dual-center experience with 176 consecutive patients.

摘要

OBJECTIVES: To determine the incidence of benign pathologic findings at elective partial nephrectomy for renal masses thought to be renal cell carcinoma (RCC) on preoperative imaging in Japanese patients. METHODS: From 1993 to 2007, 176 patients (46 women and 130 men) underwent elective partial nephrectomy for presumed RCC masses in 2 Japanese centers. The mean size of the resected lesions was 2.3 cm (range 0.3-5.8). Overall, 97 and 79 patients had a renal mass of < or = 2 cm and > 2 cm, respectively. Of the 176 patients, 100%, 89%, and 32% had preoperatively undergone computed tomography, ultrasonography, and magnetic resonance imaging, respectively. RESULTS: Of the 176 masses resected, the pathologic examination revealed benign findings in 19 (11%), angiomyolipoma in 10 (5.7%), oncocytoma in 5 (2.8%), complicated cysts in 2 (1.1%), and a solitary fibrous tumor and scar of the kidney 1 each (0.6%). Of the 46 women, 12 (26.1%) had benign lesions compared with 7 of the 130 men (5.3%; P = .0003). Of the 10 angiomyolipomas diagnosed, 8 were diagnosed in women (P = .0004). Tumor size was not associated with benign histologic findings. The incidence of benign lesions was equivalent (10% and 12%) between the 2 centers. CONCLUSIONS: The present incidence (11%) of benign lesions in presumed RCC masses at surgery in Japanese patients was lower than the incidence of 20%-30% previously reported from Western countries, probably because of the low incidence of oncocytomas in Japanese patients. Women had almost 5 times the likelihood of having a benign lesion compared with men, because of the high incidence of angiomyolipomas in women.