CASE OF THE MONTH
Primary diffuse large B-cell lymphoma of the CNS


Patient is a 66 year-old gentleman who presented with numbness, and tingling right side of the neck and right trunk. He reported no headache, visual changes or dizziness. CNS imaging studies showed two well defined oval-shaped masses at left sylvian superior ramus and high parietal region with largest measuring 18.9 mm at the latter location.
Left parietal craniotomy/biopsy was performed. Microscopic examination of the lesion showed diffuse proliferation of large cells with a starry sky pattern. The malignant cells exhibited dispersed chromatin and multiple peripherally situated nucleoli.

Immunohistochemical studies showed the malignant cells were positive for CD20, CD10, BCL2, BCL6, Mum1 (subset). A Ki-67 stain showed high proliferation index - more than 99% in the malignant cells. Fluorescence in situ studies indicated no MYC rearrangement, no BCL-2 rearrangement, and no BCL6 rearrangement. The diagnosis is primary diffuse large B-cell lymphoma (DL BCL) of the CNS, with high grade features.
Submitted by Ruobing Xiao, M.D.
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