CNS Lymphoma

Question 1

How can CNS lymphoma be divided?

Answer 1

Primary (PCNSL) or secondary (but both are pathologically identical).

Question 2

Does CNS spread occur early or late in non-CNS lymphoma?

Answer 2

Typically late. Majority are non-Hodgkin’s.

Question 3

Is PCNSL common?

Answer 3

No, 1-2% of all brain tumours, however incidence is rising relative to other brain tumours (partially due to AIDS and transplant patients).

Question 4

Where are common supratentorial locations for PCNSL?

Answer 4

1. Frontal lobes;
2. Deep nuclei;
3. Periventricular;
4. Corpus callosum.

Question 5

Where are common infratentorial locations for PCNSL?

Answer 5

Cerebellum is the most common location.

Question 6

What conditions are associated with increased risk of PCNSL?

Answer 6

1. Collagen vascular diseases (SLE, RA etc);
2. Immunosuppression;
3. Epstein-Barr virus.

Question 7

What are the commonest manifestations of CNS lymphoma?

Answer 7

1. Epidural spinal cord compression;
2. Multiple cranial nerve deficits (carcinomatous meningitis);
3. Seizures in up to 30%.

Question 8

What are the histological features of CNS lymphoma?

Answer 8

1. Tumour cell cuffs around blood vessels;
2. Multiplication of basement membranes;
3. Immunohistochemistry differentiates B-cell from T-cell lymphomas.

Question 9

What are the characteristic imaging locations of CNS lymphoma?

Answer 9

1. Majority occur in 1 or more cerebral lobes (in grey or white matter);
2. 25% occur in deep midline structures;
3. 25% are infratentorial;
4. Up to 30% have multiple lesions at presentation.

Question 10

What are the CT characteristics of PCNSL?

Answer 10

1. Homogeneously enhance (non-AIDS);
2. Up to 75% may be in contact with ependyma or meninges, giving a “pseudomeningioma patter”;
3. AIDS related: Necrotic centre, multiple ring enhancing lesions, but thicker wall than abscess.

Question 11

What are the MRI features of PCNSL?

Answer 11

No pathognomonic feature. Typically enhance. Bright on DWI.

Question 12

What evaluation should patients have after diagnosis of PCNSL?

Answer 12

1. Physical exam of all lymph nodes;
2. Imaging of all perihilar and pelvic lymph nodes;
3. Routine blood and urine;
4. Bone marrow biopsy;
5. MRI of whole neuraxis;
6. Testicular ultrasound (males);
7. Ophthalmologic examination (uveitis, intraocular lymphoma).

Question 13

Does surgical resection alter prognosis?

Answer 13

No. Main role is biopsy and tissue diagnosis.

Question 14

What role does radiation therapy have for PCNSL?

Answer 14

WBRT is the standard treatment after biopsy. Doses slightly lower than for other primary brain tumours.

Question 15

Is survival improved by adding chemotherapy to radiation therapy?

Answer 15

Yes, in non-AIDS cases. Intraventricular methotrexate may result in even better survival than intrathecal.

Question 16

What is the prognosis for PCNSL?

Answer 16

1. No treatment: median survival 3 months;
2. With radiation therapy: 10 months;
3. With radiation and intraventricular methotrexate: median time to recurrence 41 months;
4. Prognosis is worse in AIDS related cases.