Ciliated Surface in the Esophagogastric Junction Zone: A Precursor of Barrett's Mucosa or Ciliated Pseudostratified Metaplasia?

We have previously reported squamous metaplasia-like change at the esophagogastric junction (EGJ). In the present study, we examined these lesions histologically and by immunohistochemistry and electron microscopy. Samples of EGJ mucosa, 3 cm long and comprising 1.5-cm long portions of both columnar and squamous mucosa, were obtained from 43 esophagectomy resection specimens. Squamous metaplasia-like change was observed in 21 (49%) of the 43 cases. The squamous metaplasia-like change was generally positive with immunohistochemical stains for tubulin and cytokeratins (CKs) 4, 7, 8, 13, and 18, and was generally negative with stains for CKs 10, 14, and 20. This pattern of immunoreactivity is very similar to that of bronchial mucosa. Also, many cilia were detected at the apices of the cells by electron microscopy in 5 (31%) of the 16 cases that were able to be examined. Therefore, squamous metaplasia-like change at the EGJ has both a similar appearance and a similar immunohistochemical profile to respiratory bronchial epithelium. These findings may suggest that squamous metaplasia-like change at the EGJ is not a precursor of Barrett's mucosa but rather is a form of pseudostratified metaplasia.