A patient exhibits an elevated count of columnar epithelial cells in the distal esophagus. What type of tissue alteration does this represent?

Explanation

The presence of columnar cells in the lower esophagus indicates metaplasia, which is the process where one differentiated cell type is replaced by another, often as an adaptive response to chronic irritation. Dysplasia refers to disordered growth and abnormal cellular architecture, while anaplasia denotes a loss of differentiation typically seen in malignant cells. Normal histology means no change in tissue structure.