Primary CNS lymphoma: B-cell in the setting of HIV infection

Case contributed by A.Prof Frank Gaillard

Presentation

Headaches.

Patient Data

Age: Adult
Gender: Male

Single image from a non-contrast CT demonstrates a peripheral hyperdense ring lesion with central low attenuation, surrounded by oedema. 

The mass in the parietal lobe is peripherally enhancing with central non-enhancement, and extensive surrounding vasogenic oedema. The enhancing rim diffusion restricts. 

Case Discussion

This patient was found to be HIV +ve man with a low CD4+ count. He underwent a biopsy of the mass. 

Histology

Microscopic Description:

Sections A1 and A2 show several small fragments of grey and white matter in which there are predominantly angiocentric, as well as diffuse, infiltrates consisting of large malignant lymphocytes. The tumor cells show high nuclear/cytoplasmic ratio, hyperchromatic nuclei, and mitotic activity. Intermixed with the large tumor cells are small, uniform in morphology, reactive-appearing lymphocytes. There are areas of tumor necrosis, as well as numerous apoptotic nuclei.

Immunohistochemistry shows strong immunoreactivity of tumor cells for CD20, consistent with B cell lymphoma. CD3-positive reactive T cells of the CD4+ phenotype are intermixed with neoplastic B lymphocytes. A large number of tumor cells show strong nuclear immunoreactivity for MIB-1 and several, although not all, tumor cells are positive for p53. Several tumor cells are immunopositive for Ebstein-Barr viral antigen and many express CD43. The CD10 and BCL6 immunohistochemistry is negative. The infiltrated neuropil shows reactive gliosis. Special stains for bacteria, fungi and acid-fast bacilli are negative.

Final Diagnosis: Large B cell lymphoma.​

 

The key teaching point of this case, is that in immunocompromised patients, CNS lymphoma can have variable appearances, and is often centrally non-enhancing. 

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Case information

rID: 5374
Case created: 9th Jan 2009
Last edited: 3rd Dec 2015
Inclusion in quiz mode: Included

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