1. Department of Urology, Yamagata University Faculty of Medicine, Yamagata 990‑9585, Japan
2. Department of Urology, Yamagata Prefectural Kahoku Hospital, Yachi, Kahoku 999‑3511, Japan
3. Department of Pathological Diagnostics, Yamagata University Faculty of Medicine, Yamagata 990‑9585, Japan