Posterior mediastinal esophageal right paracentral slightly dense mass can be divided into non-neoplastic lesions and neoplastic lesions. 1. Non-neoplastic lesions are mostly various types of cysts, such as bronchial cysts, esophageal cysts, which are rare in the posterior mediastinum. Most of the cysts are round or round-like, and their density on CT is related to the nature of the contents of the cysts, which is usually watery density. If the protein content in the cysts is more, or combined with infections or hemorrhage, it may also be slightly high or high density, and the enhancement scan is not enhanced. 2. Common posterior mediastinal neoplastic lesions include neurogenic tumors, metastatic tumors, and tumors of esophageal origin. (1) Neurogenic tumors are the most common tumors in the paravertebral space of the posterior mediastinum, which are mainly classified into two categories: peripheral nerve and sympathetic nerve. Peripheral nerve tumors mainly include nerve sheath tumors, neurofibromas, etc. Sympathetic nerve origin tumors mainly include ganglion cell neuroma, neuroblastoma, etc. (2) Metastatic tumors are mostly seen in patients with previous history of malignant tumors. (3) If the occupation is closely related to the esophagus, it may be a tumor originating from the esophagus. Generally, after the lesion is detected by CT plain scan, it is recommended to do enhancement scan to clarify the type of enhancement of the lesion and its relationship with the surrounding structures, so as to help assist the doctor to further clarify the diagnosis.