Which of the following statements regarding the pathology of esophageal carcinoma is/are correct?

C. Patients with Barrett's metaplasia are 40 times more likely than the general population to develop adenocarcinoma

DISCUSSION: Histologically, 95% of esophageal cancers worldwide are squamous cell carcinomas, but the incidence of adenocarcinoma is increasing dramatically in the United States and Europe. Squamous cell carcinoma predominates in the upper and middle thirds of the esophagus, whereas adenocarcinoma is the most frequent distal esophageal cancer. A columnar lined lower esophagus (Barrett's metaplasia) is associated with an incidence of adenocarcinoma approximately 40 times greater than that of the general population. Esophageal cancer is a biologically aggressive tumor that characteristically metastasizes widely to regional and distant lymph nodes as well as to liver and lungs. Recognized premalignant esophageal lesions include achalasia, radiation esophagitis, caustic stricture, Plummer-Vinson syndrome, leukoplakia, esophageal diverticula, and Barrett's metaplasia. All but Barrett's metaplasia are associated with the development of squamous cell carcinoma.