“…They described four cases who showed cerebral ischemia as the acute onset of painless and massive rectal bleeding [ 1 ]. Since then, substantial numbers of case series and clinical studies have been reported in Asian countries [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ], and more recently, some reports have indicated that AHRU also exists in Western countries [ 14 , 15 , 16 , 17 ]. Currently, AHRU is recognized to be characterized by sudden onset, painless, massive, and fresh rectal bleeding, which frequently occurs in elderly patients with serious complications [ 6 , 9 , 12 ].…”