Primary central nervous system lymphomas
Primary central nervous system lymphoma (PCNSL) is a malignant tumor that affects the brain, spinal cord, or meninges. It can occur in both immunocompetent and immunocompromised individuals, with a significant association with conditions such as acquired immunodeficiency syndrome (AIDS) and organ transplantation. The risk factors for developing PCNSL largely revolve around immunosuppression, which increases the likelihood of this disease, particularly in populations with weakened immune systems. Symptoms can vary based on the tumor's location and may include headaches, seizures, and neurological impairments.
Diagnosis typically involves brain magnetic resonance imaging (MRI) and requires histopathological confirmation for accuracy. Treatment has evolved from primarily whole brain irradiation to a combination of chemotherapy and radiation therapy, with newer targeted therapies emerging in recent years. The prognosis for PCNSL can vary widely, with survival rates depending on factors like age and immune status; untreated individuals may survive only a few months, while others may live significantly longer. Given its complexity, understanding PCNSL is crucial for both medical professionals and patients navigating this challenging diagnosis.
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Primary central nervous system lymphomas
ALSO KNOWN AS: Primary cerebral lymphomas, primary CNS lymphomas, reticulum cell sarcomas
RELATED CONDITIONS: Immunodeficient states, including acquired immunodeficiency syndrome (AIDS), organ transplantation, prolonged immunosuppressive therapy, Wiskott-Aldrich syndrome, and Sjögren syndrome
DEFINITION: Primary central nervous system lymphoma is a malignant tumor of the brain, spinal cord, or meninges; it can occur in both normal and immunocompromised patients.
Risk factors: The main risk factor for primary central nervous system lymphoma is immunosuppression, including acquired immunodeficiency syndrome (AIDS), ataxia-telangiectasia, Wiskott-Aldrich syndrome, and solid organ transplantation.
Etiology and the disease process: Primary central nervous system lymphoma, if associated with AIDS, can manifest as poorly differentiated brain masses associated with hemorrhage and necrosis, composed of B cells (B lymphocytes), although T-cell lymphomas can also occur. It is thought that the dysfunction of suppressor T cells in AIDS patients leads to this B-cell lymphocytic cancer. In patients with standard immune systems, the tumor is usually more focal, well-circumscribed, and not associated with hemorrhage and necrosis.
Incidence: Primary central nervous system lymphoma makes up less than 2 percent of all intracranial neoplasms and 1 percent of all primary non-Hodgkin lymphomas. It occurs in about 15 percent of patients with AIDS. This number has come down drastically as antiretroviral medications were introduced. The most common type of lymphoma affecting the brain is diffuse histiocytic lymphoma, also known as reticulum cell sarcoma. Primary central nervous system lymphoma is the most common brain tumor due to the human immunodeficiency virus. The incidence rate of primary central nervous system lymphomas is 0.45 per 100,000 people, with about 1,700 new cases diagnosed in the United States annually.
Symptoms: Although primary central nervous system lymphoma can occur in all age groups, the average age at which it is diagnosed in normal adults is age sixty-five, but in immunocompromised patients it is found at the younger average age of between forty-five and forty-nine. Symptoms vary depending on lesion site and include headaches, seizures, focal neurologic impairment, fatigue, vertigo, language deficits, ataxia, and behavioral abnormalities.
Screening and diagnosis: Brain magnetic resonance imaging (MRI) findings often include periventricular and deep gray matter lesions with masses usually less than 2 centimeters in AIDS patients and greater than 2 centimeters in non-AIDS patients. Diagnosis requires histopathological confirmation.
Treatment and therapy: Whole brain irradiation was the standard therapy for primary central nervous system lymphomas, but this has been replaced mainly by a combination of chemotherapy and radiation therapy. Chemotherapeutic medications include dexamethasone, high-dose methotrexate, and cytarabine. In the 2020s, targeted therapies, including rituximab, nivolumab, or ibrutinib, are also used, as well as CAR-T cell therapies.
Prognosis, prevention, and outcomes: Survival rates depend on several factors, including age and immunocompetence. If left untreated, survival time can be as little as three months, while in other patients, survival time may be up to forty-four months.
Bibliography
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Hayat, M. A., editor. Tumors of the Central Nervous System. Dordrecht: Springer, 2012.
Mandal, Shobha, et al. "A Case Report on Primary Central Nervous System Lymphoma in Immunocompetent Individual." Cureus, vol. 13, no. 6, 2021, doi.org/10.7759/cureus.15990. Accessed 1 Jul. 2024.
Norden, Andrew D., David A. Reardon, and Patrick Y. C. Wen, eds. Primary Central Nervous System Tumors: Pathogenesis and Therapy. New York: Humana, 2011.
Prica, Anca, et al. "Combined Modality Therapy versus Chemotherapy Alone as an Induction Regimen for Primary Central Nervous System Lymphoma: A Decision Analysis." British Journal of Haematology, vol. 158.5, 2012, pp. 600–07.
“Primary CNS Lymphoma Treatment.” National Cancer Institute, 25 May 2023, www.cancer.gov/types/lymphoma/patient/primary-cns-lymphoma-treatment-pdq. Accessed 1 July 2024.
Shibamoto, Y., et al. "Analysis of Radiotherapy in 1,054 Patients with Primary Central Nervous System Lymphoma Treated from 1984 to 2009." Clinical Oncology, vol. 26.10, 2014, pp. 653–60.