Primary central nervous system lymphoma classification
Although Primary central nervous system lymphoma generally arises from the parenchyma, lymphomas arising primarily from the dura are termed dural lymphomas (DL). They are typically intraparenchymal. A subset of PCNSLs predominantly arises in the ventricles, with minimal parenchymal involvement.
Most of the lesions are supratentorial and periventricular, often involving deep structures such as corpus callosum and basal ganglion. Isolated intraventricular lymphoma is rare and only a few case reports.
Lymphoma of a dural genesis is a distinct variant of primary central nervous system lymphoma and is rare. It putatively has a more benign clinical course. Cranial primary dural lymphoma is more often marginal zone B-cell lymphoma, whereas spinal primary dural lymphoma is most commonly diffuse large B-cell lymphoma
Primary diffuse large B-cell lymphoma of the Central Nervous System
Primary diffuse large B-cell lymphoma of the Central Nervous System. The majority of primary central nervous system (CNS) lymphomas are diffuse large B-cell lymphomas (DLBCLs) and anaplastic large-cell lymphoma (ALCL) is a type of T-cell tumor that is rare in the CNS.
Primary central nervous system lymphoma (PCNSL) is usually a high-grade B-cell neoplasm of the large cell type (diffuse large B-cell lymphoma [DLBCL]), composed of tumor cells with apparent cytological atypia. DLBCL cells display a B-cell surface marker, CD20, as well as CD45, also known as a leukocyte-common antigen. Surface expression of CD45 is highly specific to hematopoietic cells; therefore, it may be a useful diagnostic marker to differentiate PCNSL from glioma or metastatic carcinoma in the CNS. A few reported cases of systemic B-cell lymphoma or leukemia lacked surface expression of CD45 1) 2) 3).
Primary central nervous system ALK-positive anaplastic large cell lymphoma
Primary central nervous system ALK-positive anaplastic large cell lymphoma
Similar to the findings for systemic ALCL, anaplastic lymphoma kinase (ALK)-positivity, age <40 years and chemotherapy are associated with long-term survival for ALCL of the CNS. Chemoradiotherapy including methotrexate is recommended for ALCL and the possibility of treatment with chemotherapy alone for ALK-positive ALCL is currently under consideration 4).
Immunodeficiency-associated CNS lymphoma
Immunodeficiency-associated CNS lymphoma.
Isolated primary central nervous system lymphoma arising from anterior visual pathway is very rare.