Neurenteric Cyst or Neuroendodermal Cyst? Immunohistochemical Study and Pathogenesis.

BACKGROUND Neurenteric cysts are rare central nervous system lesions derived from an endodermal origin. There is no consensus concerning pathogenesis because of the paucity of occurrences. We report an immunohistochemical study of 10 cases with neurenteric cysts and postulate its pathogenesis. METHODS Ten patients underwent surgical treatment for neurenteric cysts from 1995 to 2015. We retrospectively reviewed clinical, radiologic, operative, and pathologic findings for these patients. Immunohistochemical stains were completed in all cases to distinguish cell type and origin. RESULTS Three cell types were identified: pseudostratified-ciliated, goblet-columnar, and simple cuboidal cells. All cases were positive for cytokeratin 7, and negative for cytokeratin 20, caudal-type homeobox 2, mucin 2, thyroid transcription factor 1, human chorionic gonadotropin, placental alkaline phosphatase, and cluster of differentiation 31. Four of them had positive staining for mucin 5AC, with expression only in goblet-columnar cells. According to the immunohistochemical results, the cells resembled the respiratory tract (pseudostratified-ciliated), stomach (goblet-columnar), and respiratory bronchioles (simple cuboidal). Seventy-five percent of cases with recurrence had a goblet-columnar component, emphasizing the importance of total resection of the cyst and complete pathologic examination. CONCLUSIONS We postulate that the cystic tumor was derived from multipotent endodermal cells that migrated and traveled along the neuroectoderm, with incomplete differentiation into various cell types as a result of an unsuitable microenvironment. Because the neurenteric canal was only the channel of migration rather than a component of the cysts, the term neuroendodermal cysts is more precise in presenting the embryopathogenesis.