Endoscopy performed on a patient with persistent substernal pain despite antacid use demonstrates irregular erythematous patches several centimeters above the gastroesophageal junction. Biopsy of one of these lesions demonstrates epithelial metaplasia. Which of the following cell types was most likely observed in the involved areas?

The medical condition is Barrett's esophagus, in which the normally non-keratinizing squamous epithelium of the esophagus undergoes metaplasia to gastric or intestinal-like epithelium composed of non-ciliated columnar epithelial cells. Barrett's esophagus typically develops in the setting of chronic gastroesophageal reflux, and significantly increases the risk of later development of adenocarcinoma of the distal esophagus. Ciliated columnar epithelium is found in the respiratory tract. Cuboidal epithelium is found in the kidney, peritoneal lining, and pleural lining. Keratinizing squamous epithelium is found in skin. Ref: Wyatt C., Butterwoh IV J.F., Moos P.J., Mackey D.C., Brown T.G. (2008). Chapter 14. Gastrointestinal Pathology. In C. Wyatt, J.F. Butterwoh IV, P.J. Moos, D.C. Mackey, T.G. Brown (Eds), Pathology: The Big Picture.