Primary retroperitoneal tumors are tumors that occur in the retroperitoneal space and do not include tumors of the organs originally in the retroperitoneal space. It is a relatively uncommon tumor. Most of them are malignant, accounting for about 70%. Benign tumors such as teratoma, nerve sheath tumor and fibroma are common, while malignant tumors such as liposarcoma, fibrosarcoma, smooth muscle sarcoma, embryonal carcinoma, neurofibrosarcoma and malignant lymphoma are common. Except for a few retroperitoneal tumors, such as pheochromocytoma, which can secrete chemical mediators and produce obvious clinical symptoms that can be easily detected at an early stage, most retroperitoneal tumors are asymptomatic at the beginning. The majority of retroperitoneal tumors are asymptomatic at the beginning, but when the tumor grows gradually and produces symptoms of pressure, or is occasionally detected by the patient, the patient will seek medical attention.