NCI: A squamous cell carcinomas arising from the esophagus. It is associated with a long history of tobacco and alcohol abuse and is exceedingly rare before the age of 30. The median age is around 65 in both males and females. It is located mostly in the middle and lower third of the esophagus. Grossly, polypoid, ulcerated, plaque-like and occult lesions have been described. The microscopic features are the same as in other squamous cell carcinomas. Any degree of differentiation may occur, and variation within a single tumor is common. The prognosis is poor.