Intracranial lymphoma is a malignant tumor originating from lymph nodes or extra-lymph node organs or tissues, which is distinct from hematologic diseases. The origin of malignant lymphocytes in primary CNS lymphoma remains unclear due to the lack of lymphatic vessels and lymph nodes in the CNS, but the disease is histologically identical to systemic lymphoma and has been shown to be a non-Hodgkin’s lymphoma of B lymphocytes, of which 1-3% may have a T lymphocyte phenotype, by analysis of immunoglobulins on the surface of tumor cells. Primary intracranial lymphoma is histologically and immunohistochemically identical to systemic lymphoma, but has many differences, mainly in the following aspects: Primary central nervous system lymphoma Systemic lymphoma Classification Hodgkin’s lymphoma and non-Hodgkin’s lymphoma Non-Hodgkin’s lymphoma Pathological type B cells, T/NK cells (35%) 95-98% are B cells, T cell type is rare Clinical manifestations Local neurological deficits, increased intracranial pressure and other symptoms Enlarged lymph nodes, fever, night sweats