A 43-year-old African American woman with no significant medical history presented with 10 years of rectal pain. Initially, the pain was intermittent, mainly associated with her menstrual period, but recently it had become chronic and debilitating. No bleeding or discharge was observed. A perianal examination showed no fistula, abscess, or hemorrhoids. There was no tenderness on palpation. Colonoscopy revealed a diverticulum of the left anorectal wall with a 5-mm opening, which everted on suctioning. Radial endoscopic ultrasonography revealed a tubular anechoic area in the perirectal space along the left anorectal wall.