Primary CNS lymphoma

Case contributed by Assoc Prof Frank Gaillard


Right sided weakness.

Patient Data

Age: 61
Gender: Female

Hyperdense periventricular lesion with surrounding edema and mass effect. 


Multifocal bilateral centrum semiovale (frontal and parietal) and deep periventricular white matter enhancing bright FLAIR abnormalities. Larger lesions line left lateral ventricle body (36x16mm axial) and trigone (17x14mm axial). The anterior lesion has subependymal spread along floor of left lateral ventricle to involve the fornix body at midline, and shows diffusion restriction along its deep aspect and patchy mild increased blood volume. Small area of patchy enhancement also seen along left temporal horn. The 2 larger enhancing lesions are T2 and FLAIR hypointense, and their superolateral borders have a linear streaky enhancing pattern along a vascular alignment. The left frontal enhancing lesion is also linear.

Bright FLAIR signal are marked around the enhancing lesions, extending into left parietal lobe, striatocapsular region, and thalamus to its pial surface with the 3rd ventricle. No susceptibility artefact associated with these lesions.

There is slight left lateral ventricle effacement. Minimal midline shift at level of foramen of Munro. No hydrocephalus.

Markedly increased Lac/lipid, slightly increased Cho and reduced NAA in some areas but not all. This is nonspecific trace, but would represent neoplasm in setting of other MRI findings.


Findings most favor cerebral lymphoma.

Case Discussion

The patient went on to have a biopsy. 



Paraffin sections show pieces of white matter. There is a dense infiltrate of atypical lymphocytes around some of the blood vessels and infiltrating the brain parenchyma. The atypcial lymphocytes have scant cytoplasm, contain moderate to large nuclei with irregular nuclear membranes and containing variable numbers of conspicuous nucleoli. There is scattered apoptotic debris and few mitoses are seen. In other areas the brain parenchyma is infiltrated by plasma cells and macrophages.

The tumor cells are CD20+, MUM-1+. A large proportion of atypical cells are BCL-2+ and there is patchy BCL-6 positivity. There are no CD10 positive atypical cells. There is a background population of CD3 and CD5 positive reactive T-cells. The Ki-67 proliferative index is approximately 80%.

The features are of a diffuse large B-cell lymphoma (DLBCL) of activated B-cell (ABC) type.


Diffuse large B-cell lymphoma of activated B-cell type.

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Case information

rID: 32963
Published: 24th Dec 2014
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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