Primary CNS lymphoma

Case contributed by Frank Gaillard


Decreased conscious state.

Patient Data

Age: Older adult.

Selected images from an MRI demonstrate widespread enhancing lesions that also have diffusion restriction. Many are periventricular and there is involvement of the corpus callosum. 

The patient had a biopsy of the right temporal lobe and cerebellum. 


Sections show pieces of cerebellar tissue and cerebellar white matter. These structures show variable lymphoid infiltrates that are both superficial as well as perivascular and also intraparenchymal. The infiltrates are most prominent within block B. The individual cytologic characteristics range from mild to more pronounced nuclear pleomorphism. Some scattered mitotic figures are seen. T-cell infiltrates are highlighted by the CD3 immunoperoxidase study. The B-cell infiltrates are predominant and are highlighted by the CD20 immunoperoxidase study. There is no diagnostic evidence of demyelination in the LFB, LFB/Bielschowsky and Bielschowsky-stained sections.

Final Diagnosis: diffuse large B-cell CNS lymphoma.

Two weeks following treatment with steroids.


MRI obtained just 2 weeks after right temporal lobe biopsy and chemotherapy including steroids demonstrates a striking reduction in size and conspicuity of enhancing lesions. 

CNS lymphoma is very sensitive to steroids, at least transiently. This can prove problematic if steroids are started for edema/swelling prior to biopsy as not only does enhancement almost vanish but it makes histological assessment difficult. As such, if lymphoma is suspected, steroids should be avoided if possible until tissue has been obtained. 

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