Primary Central Nervous System Lymphoma
Background
What are the incidence and median age at Dx of primary central nervous system lymphoma (PCNSL)?
1,000 cases/yr of PCNSL (2% of all CNS tumors); median age 55 yrs (immunocompetent) vs. 35 yrs (immunocompromised)
What is the gender predilection, and how does it relate to immunocompetency?
Immunocompetent pts: males > females (2:1)
AIDS pts: 95% males
What risk factors are often associated with CNS lymphoma?
Immunodeficiency (congenital or acquired) and EBV infection
What type of non-Hodgkin lymphoma (NHL) is most often associated with PCNSL?
Diffuse large B-cell lymphoma is most often associated with PCNSL.
What % of PCNSL has ocular involvement?
15% of PCNSL has ocular involvement (vitreous, retina, choroid > optic nerve) that is typically bilat.
What is the most common genetic alteration seen in PCNSL?
The most common genetic alteration in PCNSL is the gain of chromosome 12 (12p12-14), which corresponds to the amplification of MDM2 to enhance p53 suppression
If the pt presents with ocular lymphoma, what % later develop CNS involvement?
75% of pts who present with ocular lymphoma develop CNS involvement.
With what is orbital lymphoma often associated?
Systemic NHL is often associated with orbital lymphoma.
What % of pts present with isolated spinal cord/meningeal involvement?
<5% of pts present with isolated spinal cord/meningeal involvement–a rare occurrence.
What proportion of pts present with CSF involvement?
One third of pts present with CSF involvement.
What % of pts present with PCNSL but have a negative systemic lymphoma workup?
Nearly all pts (>95%) who present with PCNSL have a negative lymphoma workup, so if lymphoma is found outside the CNS, it is NHL with involvement of the CNS.
What are the high-risk features of systemic NHL that increase the risk of CNS mets?
Burkitt, lymphoblastic lymphoma, immunocompromised pt, BM+, parameningeal presentation (nasopharynx, paranasal sinuses), and testicular relapse
What % of pts present with multifocal Dz?
Immunocompetent pts: 50%
AIDS pts: 100%
What % of pts with grossly unifocal Dz are actually microscopically multifocal?
>90% of pts with grossly unifocal Dz are microscopically multifocal.
What % of AIDS pts develop CNS lymphoma?
2%–13% of AIDS pts develop CNS lymphoma. Invariably all are EBV+.
What kind of lymphoma is PCNSL?
PCNSL is considered an extranodal NHL.
What has happened to the incidence of PCNSL over the last 30 yrs?
There has been a dramatic increase (30-fold) in immunocompetent and immunocompromised PCNSL pts.
In what regions of the CNS does PCNSL arise?
Brain, spinal cord, leptomeninges, and globe (retina, vitreous)
What virus has been associated with PCNSL?
EBV has been associated with PCNSL (60% of immunocompromised cases).
Are B cells normally found in the CNS?
No. They develop as part of the pathologic process.
What is the more radioresistant NHL: intracranial or extracranial?
Intracranial. Per the RTOG, 8,315 pts rcv 60 Gy and 88% had in-field recurrence.
What % of PCNSLs are supratentorial?
The majority of PCNSLs (75%) are supratentorial.
Workup/Staging
How do pts with CNS lymphoma present?
Focal neurologic deficits (70%), neuropsychiatric/personality change (frontal lobe involvement [43%]), ↑ICP ([33%] HA, n/v, CN VI deficit, blurred vision), seizures, leg weakness, urinary incontinence/retention, and ocular Sx (blurry vision)
All PCNSLs are what stage?
All PCNSLs are stage IE.
What brain location and specific structures are commonly involved?
The #1 location is the frontal lobe, often the deep white matter and frequently periventricular (↑CSF spread).
What are considered deep structures of the brain according to the International Extranodal Lymphoma Study Group (IELSG)?
Corpus callosum, basal ganglia, brain stem, and cerebellum
How is the Dx of ocular lymphoma made?
The Dx of ocular lymphoma is made by vitrectomy.
What infectious etiology is often confused with CNS lymphoma?
Toxoplasmosis is the infectious etiology often confused with CNS lymphoma.
What is the DDx?
Secondary metastatic lymphoma, other primary brain tumors, metastatic carcinoma, abscess, hemorrhage, multiple sclerosis, sarcoidosis, and toxoplasmosis in AIDS
What is the workup of a pt suspected of having CNS lymphoma?
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