Types Sixty percent of esophageal cancers appear in the cells lining the esophageal tube (squamous cells), usually in the upper two-thirds of the esophagus. About 40 percent develop in the glands (adenocarcinoma) in the lower third. One to 2 percent are relatively rare tumors, such as melanoma, primary lymphomas or tumors in the smooth muscles, among others. Barrett's esophagus is a premalignant condition thought to be caused by chronic inflammation where the normal squamous epithelium (lining of the esophagus) is replaced by glandular (columnar) epithelium resembling the stomach lining.