PMC3222263_01
Brain MR imaging. (a) Post-contrast axial T1-weighted image shows a homogenously enhancing extra-axial dural-based mass (m) in the right frontal region. The thickening and enhancement of the dura extends anteriorly along the falx and along the left frontal lobe (long arrows). There is also subtle enhancement extending into a few of the adjacent cortical sulci (short arrows). (b) Corresponding axial fluid-attenuated inversion recovery (FLAIR) image reveals abnormal hyperintensity within the cortical sulci (arrows) adjacent to the lesion, corresponding to subtle enhancement in A). (c) Non-enhanced axial T1-weighted image at a slightly higher level demonstrates loss of normal bone marrow hyperintensity in the calvarium adjacent to the dural mass and in the left parietal bone (long arrows). Note normal bright bone marrow (short arrows). (d) Corresponding diffusion-weighted image (DWI) reveals signal intensity similar to the dural mass within the affected bone marrow (long arrows). Note normal bone marrow without any signal (short arrows). (e) Corresponding apparent diffusion coefficient (ADC) map shows that the diffusion of water molecules within the affected bone marrow is similar to the dural lesion (long arrows). Normal bone marrow remains black without any signal (short arrows).
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F1
There was no significant edema around the lesion, which was initially felt to be consistent with an en plaque meningioma (Figure 1).
Morphology and immunohistochemical staining of dural mucosa-associated lymphoid tissue (MALT lymphoma) (a) At low magnification there is a diffuse lymphocytic infiltration of the dura with characteristic perivascular pattern. Follicular structures were not identified. (original magnification x100). (b) At higher magnification the neoplastic cells can be seen to exhibit a morphologic spectrum with abundant pale agranular cytoplasm and small to medium-sized nuclei with round to irregular nuclear borders. Rare large centroblast-like cells and plasma cells are present (original magnification x400). (c) CD20 immunohistochemical stain shows diffuse positivity (original magnification x50). (d) CD3 immunohistochemical stain shows only scattered positive cells (original magnification x50).
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F2
The pathology was consistent with MALT lymphoma expressing CD20, CD52, CD19, and CD38, but not CD5, with kappa light chain restriction (Figure 2).
PCR amplification of the variable region of the B-cell receptor heavy chain resulted in a single band for tissue taken from the orbit, lymph node and dura, demonstrating that rearrangement has occurred and the B-cells are monoclonal. PCR of the bone marrow failed to yield a defined single band.
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F3
PCR amplification of the variable region of the B-cell receptor heavy chain (according to published methods,) resulted in a single band of about 250 base pairs on gel electrophoresis (Figure 3). PCR of the bone marrow failed to yield a defined single band.