Rare case of a primary non-dural central nervous system low grade B-cell lymphoma and literature review

Abstract

We present a case of a 70-year-old HIV negative man with a five-year history of progressive dysnomia and new onset right extremity numbness, dysarthria, and blurry vision. On magnetic resonance imaging (MRI), an infiltrative enhancing tumor was noted. Follow up brain biopsy results revealed a small lymphocytic infiltrate with scattered plasma cells in a predominantly perivascular growth pattern. Flow-cytometric findings revealed a lambda monotypic B-cell population. The morphology and the flow cytometric findings were consistent with involvement by a low grade B-cell lymphoma. Subsequent positron emission tomography (PET) studies along with bone marrow biopsy and serum protein electrophoresis showed no evidence of systemic disease. The above findings are consistent with involvement by a non-dural extranodal marginal zone B-cell lymphoma (MZBCL) primary to the central nervous system (CNS). This is the first reported case of a primary CNS MZBCL with flow cytometric analysis. A review of literature on this rare entity is also included.

Keywords: Primary Non-Dural Central Nervous System Low grade B-cell lymphoma; extranodal marginal zone lymphoma.

Figure 1

3 Tesla MRI imaging of the brain. A. Axial fat-saturated postcontrast Tl-weighted image shows the 3.5 × 2.9 cm infiitrative enhancing tumor centered in the left posterior putamen, left posterior subinsular region, and adjacent left mid temporal region. B. Axial T2-weighted image shows extensive associated vasogenic edema, with relatively little mass effect.

Figure 2

Microscopic and selected immunohistochemicai features. Multifocal and angiocentric lymphoplasmacytic infiltrate at 1OOx and 400x; CD20 reactive lymphocytes; There is lambda light chain restriction; Less than 10% of the cells are reactive with Ki67.

Figure 3

Flow cytometry. Monotypic CD19 positive B-cells that have a kappa:lambda ratio of 1:5 (Note: Lambda restricted B-cells are highlighted within the red circle).