Secondary central lymphoma (SCNSL), i.e., central invasion of lymphoma, has a very poor prognosis with a median survival of 1-4 months. The occurrence of SCNSL is mainly related to the type of pathology (lymphoblastic lymphoma LBL, Burkitt’s lymphoma Burkkitts), the primary site of lymphoma (e.g., testis, bone marrow, paranasal sinus and breast, especially testicular NHL is closely related to the occurrence of SCNSL), the stage, and the level of LDH. The association with high risk of IPI and elevated LDH levels. For highly malignant lymphoblastic lymphoma and Burkkitts lymphoma, the incidence of central involvement was as high as 30-50% in the early years due to chemotherapy regimens, mostly in the meninges and spinal membranes, and deep brain parenchymal invasion was less common. In recent years, after switching to new regimens with increased dose density and high-dose MTX and intrathecal injection of chemotherapeutic agents, the proportion of CNS invasion has decreased significantly; for the most common clinical subtype of diffuse large B-cell lymphoma (DLBCL), the incidence of SCNSL is generally reported to be 2.2%; European phase III clinical studies have shown that the proportion of CNS involvement in the group receiving ACVBP chemotherapy is The proportion of CNS involvement was less in the group receiving ACVBP chemotherapy than in the CHOP group. It has also been shown that prophylactic intrathecal injections in DLBCL patients do not reduce the incidence of central invasion, and therefore, with the exception of LBL and Burkitts’ lymphoma, central prophylaxis is generally not recommended for adult NHL. Based on current data statistics, the use of Rituximab at first treatment did not reduce the incidence of SCNSL. The diagnosis of SCNSL is still mainly based on medical history, clinical manifestations related to CNS involvement and cerebrospinal fluid to find tumor cells. CSF flow cytometry, β2-MG and PCR are helpful for early diagnosis. Patients often have neurological symptoms and signs such as neurolocalization signs, psychiatric symptoms, convulsions, ocular symptoms and increased intracranial pressure. 85% of patients have increased protein in cerebrospinal fluid examination, and elevated β2-MG suggests a high possibility of central invasion. The rate of positive cytology is 0-50%, but the rate of false negative cytology is high, and if cytology is positive it often indicates extensive meningeal invasion. Some studies have reported that detection of CDRIII of malignant tumor cells in the cerebrospinal fluid by PCR can improve the diagnosis of SCNSL. If a patient has a history of NHL and neurological abnormalities, the possibility of central involvement of NHL should be considered despite a negative cerebrospinal fluid examination. There is no standard treatment protocol for secondary NHL. Clinical treatment requires both control of systemic lesions and active management of central nervous system involvement, making treatment more difficult than for primary CNS NHL. The treatment still considers systemic chemotherapy with high-dose MTX as the main drug, combined with intrathecal injection of MTX and Ara-C, and the control of systemic recurrent lesions according to the specific situation. The Sidney Kimmel Comprehensive Cancer Center has reported the use of autologous and allogeneic hematopoietic stem cell transplantation, in which 40% of patients were transplanted with allogeneic hematopoietic stem cells, resulting in 36% 5-year EFS and 39% 5-year OS in 37 patients. In addition, liposomal Ara-C, MTX, and Dexamethasone have been reported to be injected into the lateral ventricular Ommaya reservoir to further improve outcomes. Another phase I clinical study showed that 6 of 9 patients with recurrent central NHL achieved cytologic remission by Ommaya reservoir lateral ventricular injection of Rituximab, and 4 of them achieved CR. The results showed that 7 cases of PCNSL were effective and 3 cases of SCNSL also showed significant improvement, which is worth further investigation. In conclusion, the combination of high-dose MTX chemotherapy with whole-cranial radiotherapy and intrathecal injection of chemotherapeutic agents, intrathecal injection of liposomal Ara-C and Rituximab is a new attempt in the treatment of PCNSL. The light of day.