Dural MALT lymphoma with disseminated disease

Abstract

Central nervous system (CNS) lymphoma involving the dura mater is very rare and histologically is usually a subtype of non-Hodgkin's lymphoma (NHL) termed mucosa-associated lymphoid tissue (MALT) lymphoma. We present a case of a 46-year old woman with dural MALT lymphoma that was found to also involve a lacrimal gland, inguinal lymph nodes, and bone marrow. Magnetic resonance imaging of the brain showed an extra-axial enhancing mass approximately 6 cm in maximum diameter along the right frontotemporal convexity. Histopathology of the resected dural mass showed MALT lymphoma expressing CD20, CD52, CD19, and CD38. Molecular studies of the B-cell receptor heavy chain demonstrated monoclonality at the involved sites. The patient was treated with four cycles of fludarabine, mitoxantrone, and rituximab with complete remission. She had recurrence in the subcutaneous tissue of the back at 12 months but has remained free of intracranial disease for 31 months. A review of the literature reveals 57 cases of dural MALT lymphoma. Only 4 had extra-CNS involvement at presentation, and only 3 had local recurrence of the dural tumor. Because of the indolent behavior of this tumor, the intracranial portion can be treated conservatively after resection with or without chemotherapy. Deferral of brain radiation can be considered with close clinical and neuroimaging follow up.

Keywords: Chemotherapy; Dural lymphoma; MALT lymphoma; Meningioma.; Radiation.

Figure 1

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).

Figure 2

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 ×100). (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 ×400). (c) CD20 immunohistochemical stain shows diffuse positivity (original magnification ×50). (d) CD3 immunohistochemical stain shows only scattered positive cells (original magnification ×50).

Figure 3

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.