Spread of malignant lymphoid cells into rat central nervous system with intact and disrupted blood-brain barrier

Secondary central nervous system lymphoma surrounding a region injured by subarachnoid hemorrhage and subsequent aneurysmal clipping

The present case study describes a rare case of secondary central nervous system (CNS) lymphoma that infiltrated the dura and leptomeninges around the area injured by subarachnoid hemorrhage and subsequent aneurysmal clipping. Invasion of the CNS was observed by computed tomography as slurred fissures of the right parietal lobe adjacent to the surgery area. Subdural and subarachnoid enhancement overlapping the area injured by past surgical procedures was observed by contrast-enhanced magnetic resonance imaging. Surgical resection revealed B-cell lymphoma infiltrating the dura and leptomeninges surrounding the post-hemorrhagic area. The patient was subsequently diagnosed with systemic lymphoma and bone marrow invasion, and multiple lymph node swelling. To the best of our knowledge, this is the first report of malignant lymphoma involving the CNS overlapping a previously injured area.

Summary statement on primary central nervous system lymphomas from the Eighth International Conference on Malignant Lymphoma, Lugano, Switzerland, June 12 to 15, 2002

Under the sponsorship of the International Extranodal Lymphoma Study Group, a Multidisciplinary Workshop on primary CNS lymphoma (PCNSL) with over 50 participants from Europe, North America, Israel, and Australia was held as part of the Eighth International Conference on Malignant Lymphoma in Lugano, Switzerland (June 12 to 15, 2002). The main purposes of the Workshop were to exchange the latest scientific information, to analyze methodologic issues in the design of clinical trials, to reach a consensus on treatment recommendations and prognostic factors, to discuss clinical and molecular targets for future studies, and to establish an international collaborative group to conduct laboratory and clinical investigations in PCNSL. This article summarizes the contents of the Workshop, analyzes the current knowledge on the most relevant biologic and clinical issues in PCNSL, and focuses on fundamental challenges to be addressed in future studies.

Role of genetic background in P selectin-dependent immune surveillance of the central nervous system

Although the blood-brain barrier and blood cerebrospinal fluid barrier maintain the central nervous system (CNS) as an immunologically privileged site, T lymphocytes can migrate through unstimulated brain endothelium and epithelium to perform immune surveillance or initiate inflammation. Our prior results suggested that early CNS migration of a CD4 Th1 cell line was facilitated by P selectin (CD62P) in (PL/JxSJL/J)F1 mice. Here, quantitative analysis of migration 2 h following adoptive transfer of fluorescently labeled cells revealed a 53-72% decrease in activated splenocyte, CD4 Th1 and CD8 migration, but not CD4 Th2, in CD62P-deficient C57BL6/J mice. Immunohistochemistry revealed constitutive expression of CD62P within the meninges and choroid plexus epithelia in C57BL6/J and SJL/J, but not BALB/cJ, mice. Activated splenocyte migration was approximately three- to four-fold greater in SJL/J as compared to BALB/cJ mice. Anti-CD62P treatment normalized this difference. Based on these results, we hypothesize that genetically determined kinetics of immune surveillance may regulate the phenotype of subsequent CNS inflammation.

New animal models to probe brain tumor biology, therapy, and immunotherapy: advantages and remaining concerns

New genetic models provide better biological mimics of human tumors. The new models can give deeper insight into tumorigenesis and provide better targets for testing therapies. To use the new models most successfully, it is useful to keep in mind limitations that are harder to overcome by genetic manipulation. These include biochemical and anatomical differences between species, as well as differences in scale, both spatial and temporal. Three approaches to new genetic brain tumor models are described in the following articles. This essay provides a context, bringing out both advantages and remaining concerns. Examples are taken from work in brain tumor immunobiology and immunotherapy. The complementarity of different models, and the dichotomy between general principles and model-specific details are stressed.

Imaging techniques in neoplastic meningiosis

Since the introduction of CT and MRI as diagnostic aids, it has been possible to obtain direct images of neoplastic meningiosis. After more than ten years experience, the combination of MRI with the administration of a paramagnetic contrast medium is now accepted as the method of choice for the sensitive detection of meningeal diseases and for monitoring their treatment. The almost uniform character of leptomeningeal or pachymeningeal enhancement in the presence of infective, inflammatory, neoplastic, vascular or reactive changes is the reason for the restricted specificity of MRI, so that with the imaging process alone only very limited information about the etiology is available. Clinical data, laboratory findings, examination of the CSF and histopathological examination are therefore essential for interpreting the meningeal changes and making a differential diagnosis. Various pathophysiological processes can lead to a single meningeal enhancement visualizable with MRI: 1. a genuine disturbance of the blood-brain barrier is found in the presence of infection or inflammation, 2. leptomeningeal structures can be directly infiltrated by sheets or nodules of tumors, the blood vessels of which possess no intact blood-brain barrier, 3. physical or chemical irritants may produce of local inflammatory reaction with vascular proliferation and its corresponding enhancement, a 4. a pseudoenhancement may follow reactive dilatation of the vessels. In the present article the various appearances of neoplastic invasion of the meninges in MRI and their differential diagnosis will be described.

Pathogenesis and classification of primary central nervous system lymphoma: an update

Primary central nervous system lymphoma has undergone a remarkable increase in incidence over the last decade, both in immunosuppressed and immunocompetent individuals. Its clinicopathologic evaluation requires knowledge of current hematopathologic systems for lymphoma classification, as well as specific understanding of unique central nervous system determinants. In immunocompromised individuals, the tumor has a constant association with Epstein-Barr virus. The form of Epstein-Barr virus in these tumors appears to be predominantly latent, however, the precise mechanism relating virus to tumor pathogenesis is still unclear. In immunocompetent patients, risk factors and oncogenic associations are completely unknown. Critical to the formation of these tumors is the trafficking of B-cells, whether pre- or post-transformation, across the blood-brain barrier. These B-cell migrations may require perturbations to the barrier that originate in or around neural parenchyma, such as localized injury or infection.