A case of solitary rectal diverticulum presenting with a retrorectal mass.

Colonic diverticula are common whereas but rectal diverticula are very rare, with only sporadic reports in the literature since 1911. Most patients with rectal diverticula are diagnosed incidentally, inflammatory processes may have developed at the time of the diagnosis. We report the case of a 42-year-old woman presenting with a retrorectal mass that was detected incidentally. She was suspected of having a rectal diverticulum by transrectal ultrasonography and magnetic resonance imaging. However, the colonoscopic findings were unremarkable. A rectal diverticulum was confirmed intraoperatively, and a transanal diverticulectomy was performed.