This document discusses various types of central nervous system lymphomas. It begins by introducing CNS lymphomas and noting that 95% are diffuse large B-cell lymphomas. It then discusses primary CNS lymphoma, focusing on its etiology, pathology, clinical presentation, imaging features, and differential diagnosis. Several other specific types of CNS lymphomas are also summarized, including intravascular lymphoma, lymphomatosis cerebri, MALT lymphoma, lymphomatoid granulomatosis, and post-transplant lymphoproliferative disorder. Metastatic intracranial lymphoma is briefly covered at the end.

1. CNS LYMPHOMAS
DR.M.VINTOHKUMAR
APOLLO SPECILATY HOSPITAL

2. INTRODUCTION
 The CNS can be involved by a variety of lymphoid lesions that occur either
as primary tumors or metastatic deposits from extracranial disease.
 Together, lymphoid neoplasms comprise the sixth most common group of
CNS malignancies.
 As the CNS lacks lymphatics and lymphoid tissue, how and why lymphomas
can arise as primary CNS neoplasms is unknown.
 95% of primary CNS lymphomas (PCNSLs) are diffuse large B-cell
lymphomas (DLBCLs).
 Primary CNS lymphoma focusing on DLBCL. Non-DLBCL lymphomas,
including intravascular lymphoma, lymphomatosis cerebri, MALT lymphoma,
and post-transplant lymphoproliferative disorder (PTLD).

3. PRIMARY CNS LYMPHOMA
 Primary CNS lymphoma (PCNSL) is a rare variant of extranodal non-Hodgkin
lymphoma restricted to the brain, spinal cord, eye, and meninges.
 By definition, disease outside the nervous system is absent at the time of
initial diagnosis.

4. Etiology
 Precise origin unknown
 CNS lacks lymphatics, lymphocytes
 Increased risk with
o Viruses (EBV, HIV/AIDS)
o Congenital immunodeficiency syndromes
o Severe immunosuppression (chemotherapy, longterm steroids)

5. Pathology
 6% of all primary CNS neoplasms but increasing
 Predilection for deep brain
o Periventricular WM, basal ganglia
o Perivascular lymphoid clusters common
 Solitary (2/3), multiple (1/3)
o Multiple compartments may be involved
 Focal > diffusely infiltrating lesions
 Hemorrhage, necrosis rare in immunocompetent
 Vast majority are non-Hodgkin lymphomas
 Diffuse large B-cell lymphomas (90-95%)
o Immature blastic cells
o MIB-1 > 50
 Low-grade, Burkitt, T-cell lymphomas (5-10%)
 Primary CNS Hodgkin lymphoma rare

6. Clinical presentation
 Most patients with PCNSL present with focal neurologic deficits, altered
mental status, and neuropsychiatric disturbances.
 Seizures are less common than in patients with other primary brain tumors.
Imaging
 Contrast-enhanced cranial MR is the modality of choice in evaluating patients
with suspected PCNSL.
 As isolated spinal cord involvement is rare (3-4% of cases), spinal imaging is
indicated only in patients with myelopathy or suspected diffuse meningeal
dissemination.

7. General Features
 Findings vary with immune status.
 Steroids may mask/↓ imaging findings.
 Periventricular WM, basal ganglia common sites.
CT
 Hyperdense on NECT (immunocompetent).
 Hemorrhage, necrosis rare unless immunocompromised.
MR
 Generally isointense with GM on T1-, T2WI
 Petechial hemorrhage in immunocompetent
 Gross hemorrhage, necrosis in immunocompromised
 Strong uniform enhancement (ring in immunocompromised)
 Often restricts on DWI

8. Differential Diagnosis
 Glioblastoma multiforme, metastasis in immunocompetent
 Toxoplasmosis in immunocompromised
 Lymphomatoid granulomatosis, PTLD in transplant patients
Although both tumors often cross the corpus callosum, hemorrhage and necrosis
are rare in PCNSL.

9. PCNSL

12. The lesion restricts strongly on
DWI. 24-10D. Axial T1 C+ FS
shows that the lesion
enhances intensely, uniformly.

15. Intravascular (Angiocentric) Lymphoma
 Intravascular lymphoma (IVL) is a rare type of lymphoma characterized by
proliferating malignant cells within small and medium-sized vessels. Although
it can involve any organ, IVL typically affects the skin and the CNS.
Pathology
 Small/medium-sized vessels filled with tumor
 Little/no parenchymal tumor
 Multifocal infarcts, microhemorrhages common
Clinical Issues
 Older patients with dementia, cognitive decline, TIAs
 Skin lesions (50%).

16. Imaging
• Multifocal T2/FLAIR hyperintensities
• Hemorrhages, foci of restricted diffusion
• Linear/punctate enhancement
Common Differential Diagnoses
• PCNSL
• Vasculitis

21. Lymphomatosis Cerebri
 Lymphomatosis cerebri is an uncommon form of PCNSL. Diffuse
infiltration of lymphoma cells in both gray and white matter without a
focal mass lesion is characteristic.
 Most patients are middle-aged or elderly and present with subacute
encephalopathy or rapidly progressive dementia. Personality changes and
ataxia are common.
 Imaging findings are nonspecific with patchy and confluent T2/FLAIR
hyperintensities. Little or no enhancement is typical
 The major differential diagnosis is gliomatosis cerebri.

23. MALT Lymphoma
 Mucosa-associated lymphoid tissue (MALT) lymphomas in the head and
neck are most often ocular adnexal tumors,occurring in the conjunctiva,
lacrimal glands, orbit, and eyelids. The cranial meninges, especially the
dura, are occasional sites. Parenchymal lesions are rare.

24. Lymphomatoid Granulomatosis
Lymphomatoid granulomatosis (LYG) is a rare multisystem
angiocentric and angioinvasive lymphoproliferative disorder
characterized by atypical B-cell proliferations of uncertain malignant
potential.
Etiology
 EBV infection is a feature of most reported cases. LYG also occurs in the
setting of HIV/AIDS and in patients on maintenance immunosuppression
following solid organ transplantation

25. Imaging
 Nearly half of patients with LYG have demonstrable brain lesions on MR
imaging. Imaging findings are nonspecific, and there is no direct correlation
with LYG grade.
 The most common abnormalities are multifocal T2/FLAIR nodular
hyperintensities in the cerebral hemispheres, cerebellum, or spinal cord. The
second most common imaging finding in LYG is involvement of the
leptomeninges and cranial nerves. Dura-based masses and choroid plexus
lesions also occur.
 LYG typically enhances strongly. Both solid and ring-like patterns as well as
multifocal punctate and linear enhancing foci have been described

28. Post-Transplant Lymphoproliferative Disorder
 Post-transplant lymphoproliferative disorder (PTLD) is one of the life-
threatening complications of immunosuppressive therapy in patients with
solid organ or hematopoietic cell transplantation.
 The PTLD disease spectrum ranges from an infectious mononucleosis-like
illness with reactive lym nodehyperplasia to malignant lymphoma. Most
PTLDs are EBV-related.

29. Terminology and Etiology
 Complication of organ or stem cell transplants or Long-term
maintenance immunosuppression
 Ranges from benign mono-like illness to malignant lymphoma
Pathology
 Monomorphic or polymorphic lymphoid proliferations
 Polymorphic PTLD has plasmacytic B-cell elements of varying maturity
 Monomorphic PTLD has blastic cells → large B-cell lymphoma

30. Clinical Issues
 0.5-2.5% of patients with solid organ transplants
 5-20% with PTLD have CNS involvement
 Presents several years after transplantation
 Children > adults
Imaging
 Brain findings resemble those of AIDS-related lymphoma
 Extracranial PTLD
o Bilateral cervical adenopathy common
o Orbital, sinonasal lesions

33. Metastatic Intracranial Lymphoma
 Metastatic intracranial lymphoma is also called secondary CNS
lymphoma (SCNSL). Here the skull, meningeal, and brain lesions are
all secondary to systemic lymphoma.
SECONDARY (METASTATIC) INTRACRANIAL LYMPHOMA
 80% from high-grade systemic B-cell lymphomas Skull, dural lesions > >
brain parenchyma
 Multicompartmental disease common
 Calvaria + epidural, scalp lesions
 Skull base + nose, cavernous sinus/pituitary
 Leptomeningeal, CSF spread uncommon Spine “drop mets” (3-5%)

34.  Thank you