Moderate to severe atypical hyperplasia of the esophagus is not cancer, but it is a precancerous lesion. Esophageal atypical hyperplasia usually occurs in squamous epithelium, also known as esophageal squamous intraepithelial neoplasia, which is a precancerous lesion of esophageal squamous carcinoma, and is a histopathological staging. People with atypical hyperplasia are at a significantly increased risk of esophageal squamous carcinoma, and the incidence of carcinoma increases with the worsening of the hyperplasia lesion as it becomes more pronounced in those with severe hyperplasia. Moderate to severe atypical hyperplasia of the esophagus is a definite precancerous lesion that has a certain chance of progressing to esophageal cancer, but it is not equivalent to cancer and may not turn into cancer in properly treated patients. Patients with moderate to severe atypical hyperplasia of the esophagus should seek medical treatment as soon as possible, follow the doctor’s instructions, and undergo endoscopic radiofrequency ablation or other treatments if necessary, to control the progression of the disease and to obtain a good prognosis as far as possible.