Congenital abdominal aortic aneurysm discovered incidental to a lower back mass. Issue 1 (21st January 2018) - Kuboi, Toru; Miyagi, Megumi; Kondo, Shuji; Arioka, Makoto; Yamato, Satoshi; Sadamura, Takaaki; Jinnai, Wataru; Nakano, Akiko; Ota, Akira