Embryogenesis of enteric duplication cysts of the tongue

Abstract

Enteric duplications may be found throughout the gastrointestinal tract and may be multiple. They appear to recapitulate the architecture of the normal gastrointestinal tract. We report 2 cases of lingual enteric duplications diagnosed in childhood. Both occurred in males, one of 4 months and the other of 5 years of age. Both were relatively asymptomatic cystic swellings of the tongue. One was lined by stratified squamous nonkeratinizing epithelium that merged with gastric type epithelium, while the second was lined by large bowel type mucosa. The differential diagnosis of a tongue mass in the paediatric age group includes dermoid cyst, epidermoid cyst, neurofibroma, haemangioma, cystic hygroma, ranula, retention cyst, hamartoma, lingual thyroid and teratoma. Enteric duplication cysts are rare in the tongue (0.3%), and more frequently occur in relation to the small intestine, oesophagus, colon or stomach. The lesions may consist of only a mucosal lining, or may be invested by an entire multilayered wall of mucosa, submucosa and muscularis propria. The mucosal lining may be histologically similar to that of the segment of the gut to which it is topographically related, or heterotopic tissue (particularly gastric) may be present. Not infrequently more than one type of mucosa occurs. Enteric duplications of the tongue may form from epithelial inclusions that are retained along the lines of fusion of the embryonic primordia that contribute to the formation of the organ. Other theories of pathogenesis of enteric duplications include their development from: a) isolated lacunae, after incomplete coalescence of the spaces that form between the cells within the solid epithelial core of the developing gut tube; b) persistent intestinal epithelial buds in the submucosal connective tissue in the developing gut wall; and c) strands or masses of adherent entodermal cells caught up with the infolding of the notochordal plate during the formation of the notochord. As not all of the theories of pathogenesis of enteric duplication cysts can be applied to the tongue, it appears that enteric duplications form a heterogeneous group that may share similar morphologic features, but not necessarily the same pathogenesis. Enteric duplications may be found throughout the gastrointestinal tract and may be multiple. They appear to recapitulate the architecture of the normal gastrointestinal tract. We report 2 cases of lingual enteric duplications diagnosed in childhood. Both occurred in males, one of 4 months and the other of 5 years of age. Both were relatively asymptomatic cystic swellings of the tongue. One was lined by stratified squamous nonkeratinizing epithelium that merged with gastric type epithelium, while the second was lined by large bowel type mucosa. The differential diagnosis of a tongue mass in the paediatric age group includes dermoid cyst, epidermoid cyst, neurofibroma, haemangioma, cystic hygroma, ranula, retention cyst, hamartoma, lingual thyroid and teratoma. Enteric duplication cysts are rare in the tongue (0.3%), and more frequently occur in relation to the small intestine, oesophagus, colon or stomach. The lesions may consist of only a mucosal lining, or may be invested by an entire multilayered wall of mucosa, submucosa and muscularis propria. The mucosal lining may be histologically similar to that of the segment of the gut to which it is topographically related, or heterotopic tissue (particularly gastric) may be present. Not infrequently more than one type of mucosa occurs. Enteric duplications of the tongue may form from epithelial inclusions that are retained along the lines of fusion of the embryonic primordia that contribute to the formation of the organ. Other theories of pathogenesis of enteric duplications include their development from: a) isolated lacunae, after incomplete coalescence of the spaces that form between the cells within the solid epithelial core of the developing gut tube; b) persistent intestinal epithelial buds in the submucosal connective tissue in the developing gut wall; and c) strands or masses of adherent entodermal cells caught up with the infolding of the notochordal plate during the formation of the notochord. As not all of the theories of pathogenesis of enteric duplication cysts can be applied to the tongue, it appears that enteric duplications form a heterogeneous group that may share similar morphologic features, but not necessarily the same pathogenesis.