"These are usually found in the retrorectal space and do not communicate with the urinary tract. Cystic rectal duplications must be distinguished from cystic sacrococcygeal teratoma, tailgut cyst, and an anterior meningocele. When associated with an anorectal malformation and sacral anomalies, the cyst may be part of the Currarino syndrome. Rarely, a rectal duplication cyst presents as rectal prolapse in an infant.

"Imaging is a critical aspect of preoperative preparation. The choice of imaging is dictated by the site of the duplication, clinical urgency, and the potential for associated anomalies. Isolated small bowel duplications often require no preoperative investigations other than abdominal sonography, a plain abdominal radiograph and routine blood tests. Occasionally, a technetium-99m pertechnetate radionuclide scan is helpful in detecting heterotopic gastric mucosa. In contrast, thoracoabdominal lesions demand detailed radiologic imaging of mediastinal, abdominal, and spinal components. MRI and/or CT scans enable evaluation of the cranial and caudal extent of the cyst. Upper gastrointestinal contrast studies and endoscopy may be necessary in selected cases. The possibility of an additional intestinal duplication must be considered with foregut duplications. Magnetic resonance cholangiography or, in older children, endoscopic retrograde cholangiopancreatography (ERCP) are valuable in the assessment of pancreatic and selected duodenal duplications. Magnetic resonance angiography may assist in planning surgery for large retroperitoneal lesions. Pelvic duplications are best imaged by CT or MRI in conjunction with a contrast enema, fistulogram, endoscopy, and urinary tract sonography."

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