Columnar mucosa in the proximal esophagus.

Twelve cases of columnar mucosa occurring in the proximal esophagus are described. This lesion is more common than previously recognized and is frequently overlooked at endoscopy, possibly due to inadequate examination of the proximal esophagus. This lesion has a typical and easily recognized endoscopic appearance. Biopsy of the lesion confirms the presence of columnar mucosa, usually with parietal cells (11 of 12 cases). It does not appear to be related to Barrett's epithelium and may represent either a congenital rest or a response to recurrent trauma. Current evidence would seem to support a congenital origin.