Mycosis fungoides is a disease caused by fungal infection of the mucosal membrane of the esophagus, and the common causative agent is Candida albicans. The common causes of mycosis are: old age or wasting disease or malnutrition, such as diabetes, tumor patients, etc., resulting in a decrease in the resistance of the esophageal mucosa, more easily infected by mold, and then a long-term high dose of antibiotics, resulting in the imbalance of the body’s flora, pathogenic Candida albicans will invade the esophageal mucosa and cause infection; high dose of glucocorticoids or High doses of glucocorticoids or immunosuppressants (e.g. rheumatic or rheumatoid patients, patients with nephrotic syndrome, etc.) lead to a decrease in the number of white blood cells, especially neutrophils and macrophages, which reduces the resistance of the esophageal mucosa and can also cause fungal infection of the esophageal mucosa. Some healthy individuals may also develop esophageal mycotic infections, which may be related to their temporary decrease in immune capacity. Mycosis fungoides can present as a foreign body sensation in swallowing, chest pain, heartburn, acid reflux, nausea, or just epigastric discomfort and anorexia. An esophagoscopy can reveal a white adherent on the esophageal wall that is not easily removed. Mycosis fungoides must be taken seriously in treatment because it is not a single disease, but mostly a comorbidity of other diseases, and the treatment should pay attention to other comorbidities while using antifungal drugs.