Primary brain lymphomas, a type of primary central nervous system lymphoma, originate in neural tissue and are usually B-cell tumors. Diagnosis requires neuroimaging and sometimes cerebrospinal fluid analysis (including Epstein-Barr titers) or brain biopsy. Treatment includes corticosteroids, chemotherapy, and radiation therapy.
Incidence of primary brain lymphomas increased from 0.1/100,000 in 1975 to 0.5/100,000 in 2017 (1) among immunocompromised patients and older adults. Lymphomas tend to infiltrate the brain diffusely, often as multicentric masses adjacent to the ventricles, but may occur as solitary brain masses. Lymphomas may also occur in the meninges, uvea, or vitreous humor. Most are B-cell tumors, often immunoblastic. The Epstein-Barr virus may contribute to development of lymphomas in immunocompromised patients. Most patients do not develop subsequent systemic lymphoma.
(See also Overview of Intracranial Tumors.)
Reference
1. Lv C, Wang J, Zhou M, et al: Primary central nervous system lymphoma in the United States, 1975-2017. Ther Adv Hematol 13:20406207211066166 2022. doi: 10.1177/20406207211066166
Diagnosis of Primary Brain Lymphomas
MRI
Cerebrospinal fluid (CSF) analysis or biopsy
MRI can suggest the diagnosis of primary brain lymphoma. However, MRI may be unable to distinguish cerebral toxoplasmosis (which is common among patients with end-stage HIV infection [AIDS]) or some gliomas from lymphoma, requiring diagnosis by tissue biopsy or CSF cytology.
CSF must be examined to rule out lymphomatous meningitis if there is gadolinium enhancement on MRI or if clinical examination detects evidence of meningeal signs, particularly if cranial neuropathies are detected. In immunocompromised patients, Epstein-Barr virus DNA may be detected in CSF. If CSF does not contain lymphoma cells or Epstein-Barr virus DNA, guided-needle or open biopsy is required. Because lymphoma is initially highly sensitive to corticosteroids, giving these medications just before biopsy may cause the lesion to disappear, resulting in a false-negative biopsy. Thus, corticosteroids should not be given to patients with suspected CNS lymphoma until after definitive diagnosis, unless absolutely necessary because of acute clinical deterioration.
Staging of primary brain lymphomas involves imaging of the chest, abdomen, and pelvis; slit-lamp examination of the eye; and bone marrow biopsy to determine how far the tumor has spread.
Treatment of Primary Brain Lymphomas
Corticosteroids
Chemotherapy
Radiation therapy
Median 5-year survival is approximately 30 to 38% (1). Survival is higher among younger than older patients (2).
Treatment references
1. Lv C, Wang J, Zhou M, et al: Primary central nervous system lymphoma in the United States, 1975-2017. Ther Adv Hematol 13:20406207211066166 2022. doi: 10.1177/20406207211066166
2. Tang D, Chen Y, Shi Y, et al: Epidemiologic characteristics, prognostic factors, and treatment outcomes in primary central nervous system lymphoma: A SEER-based study. Front Oncol 12:817043, 2022. doi: 10.3389/fonc.2022.817043
