Primary CNS lymphoma
- Lesion
Primary CNS lymphoma is a B-cell cancer that starts in the brain, eyes or spinal cord, mostly in older adults or people with weak immunity.
What it is
Primary CNS lymphoma is a lymphoma confined to the brain, spinal cord, leptomeninges or eyes, without systemic disease at diagnosis. Almost all are diffuse large B-cell lymphomas that cluster around blood vessels. In immunocompetent patients, mostly older, it is EBV-negative and often driven by MYD88 and CD79B mutations; in AIDS and transplant patients it is EBV-positive. Lesions are often multiple and deep, and can involve the vitreous and retina.
Structure
- Gross: poorly defined, grey, soft periventricular masses, sometimes with central necrosis in AIDS.
- Reactive T cells and astrocytes surround the tumour; apoptotic bodies and necrosis may be prominent.
Markers
- CD20
- PAX5
- MUM1
- BCL6
- EBER (in immunosuppressed)
- Ki-67
Clinical notes
- Cognitive and behavioural changes, focal deficits and seizures; ocular involvement causes floaters and blurred vision.
- Treatment centres on chemotherapy that crosses the blood-brain barrier; surgery has little role.
Test yourself
Think of the answer, then tap the question to see it.
What is the usual histologic type of primary CNS lymphoma?
Diffuse large B-cell lymphoma with an angiocentric growth pattern.
Which virus is associated with primary CNS lymphoma in people with AIDS?
Epstein-Barr virus.
Why can corticosteroids hinder the diagnosis?
They kill lymphoma cells quickly, so the lesion shrinks and a later biopsy may not show the tumour.
Elsewhere in DurgiPedia
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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Primary Central Nervous System Lymphoma Treatment (PDQ®)–Health Professional Version (National Cancer Institute, 2026).
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Representative model, for educational purposes only.