An unusual presentation of a cystic duplication of the sigmoid colon entirely lined with squamous epithelium.

Alimentary tract duplications are rare congenital malformations that occur most commonly in the jejunoileal part of the gastrointestinal tract. Management of this pathologic condition is usually drawn up. We report a case of descending colonic communicating duplication in which clinical presentation and anatomopathologic results were unexpected. A slightly echogenic abdominal mass reaching 72 x 36 mm in the left flank was diagnosed in a female fetus during the third trimester ultrasound examination. At birth, volume of the mass rapidly evolved, and despite no intestinal obstruction was observed by compression of the adjacent gastrointestinal tract, abdomen was distended. Abdominal plain film showed a large air collection, and the barium enema demonstrated a slight leak of contrast in the aerated mass, suggesting a communication with the sigmoid colon. No other abnormalities were seen. The patient underwent surgery in emergency. The mass was then totally excised through an antimesenteric resection of the tubular tract joining cystic mass and sigmoid colon. A lateral suture of the colon was subsequently performed. The wall of the duplication is usually composed of a smooth muscle layer covered by an epithelium, mostly of intestinal type. Herein, we describe a descending colonic duplication completely lined with nonkeratinizing squamous epithelium. Therefore, the association of a colonic mucosa (of endodermic origin) and a squamous epithelium (derived from the ectoderm) in our case is an interesting finding and is not explained by the various theories. Furthermore, the clinical characteristics, diagnosis, and treatment of intestinal duplications are discussed with regard to literature.