Gender differences in benign renal masses

To examine gender-specific differences in benign renal tumors.

This retrospective study included 135 adult Caucasian patients with 143 benign renal tumors, which were treated surgically at a single institution. Demographics, comorbidity, histology, renal function, and management were compared by gender. A systematic review and meta-analysis of the literature were performed.

A total of 73 women were compared with 62 men. The female-to-male ratio was significantly higher in patients with benign renal tumors than in those with renal cell carcinoma (1.18:1 vs. 0.57:1, p < 0.001). Only 17 % of benign renal tumors were correctly classified by preoperative computed tomography. The most frequently observed histological types were oncocytoma (44 %) and angiomyolipoma (37 %). Angiomyolipoma occurred more than twice as often in women than in men (72 vs. 28 %), while oncocytoma was more frequently found in men (59 vs. 41 %, p = 0.001). Men with benign renal tumors were older (p = 0.002) and had higher body mass indices (p = 0.019), higher comorbidity indices (p < 0.001), lower ECOG performance status (p < 0.001), and smaller tumors (p = 0.045). No differences were seen in pack years, mode of diagnosis, bilaterality, renal function, use of laparoscopic surgery, and the rate of radical nephrectomy. In the meta-analysis of 9,665 renal tumors, women had a 2.55-fold increased chance of benign pathology and a greater chance of angiomyolipoma (OR 4.66) than men.

This study demonstrated several gender-specific differences in benign renal tumors, especially in the histological types. Despite this, clinical–pathological features and management of benign renal tumors in men and women appear more alike than different.