[Cystic duplication of the rectum].
Cyst or intestinal duplications can arise anywhere along the gut, however those located in the rectum are very rare and only a few dozen cases have been reported. The reason that induced us to report this patient is double: first to present a new case of rectal duplication diagnosed at 45 days old that had a normal barium enema previously, second to confirm once more that the muscular complex of the rectum can be cut in the posterior middle line without any damage to the rectal continence function, as Peña's surgical approach for anorectal atresias. The case reported correspond to a newborn weighing 2,850 grs who had exomphalos of 5 cm. Wide with an integral sac and was operated by primary closure. When he was 10 days old, and because he had some intestinal disturbances compatible with malrotation, a barium enema was done that was normal. He was discharged and returned 30 days later because of striped feces and constipation. Rectal examination showed a retrorectal tumor located at left posterolateral space. Ultrasound showed a cystic mass and barium enema displayed a narrowed rectum channel. First we did a Wangesteen colostomy. Ten days later, by a sagittal posterior approach cutting the Levator and Muscular Complex of the rectum in the middle line and without opening the lumen, a tumor like a nut, sharing its muscular coat with the rectum, was excised. The Muscular Complex and the Levator were repaired with the aid of the electrostimulator. After the 7 day postoperation we made some rectal dilatations and closure of colostomy at 21 day.(ABSTRACT TRUNCATED AT 250 WORDS)