Extranodal marginal zone lymphoma of the dura mater with IgH/MALT1 translocation and review of literature

Abstract

Primary central nervous system lymphoma (PCNSL) is an extranodal non-Hodgkin lymphoma involving brain, intraocular structures and spinal cord, without evidence of systemic disease. The majority of PCNSLs are diffuse large B-cell type. We encountered a rare case of primary dural marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) with extension into the brain in a 59-year-old man. A magnetic resonance imaging scan showed a 22-mm tumor located in the left posterior temporal lobe extending from the dura. Histopathology revealed a lymphoplasmacytic infiltration of the dura and the brain parenchyma in a perivascular pattern. Immunohistochemical and in situ hybridization studies showed a B-cell phenotype with kappa light chain restriction. Fluorescent in situ hybridization study showed a t(14;18)(q32;q21) with immunoglobulin heavy-chain/MALT1 fusion. The molecular study for immunoglobulin heavy-chain gene rearrangement by polymerase chain reaction showed a clonal gene rearrangement.

Fig. 1

Morphologic, immunohistochemical, Ig light chain expression and FISH assay of the PCNS MALT lymphoma. A and B Histopathology of the lymphoma showing a prominent lymphoplasmacytic infiltration with a characteristic perivascular pattern (hematoxylin–eosin, original magnification, ×100 and ×400). C and D Many of the lymphoma cells were positive for CD 20 and CD 79a (immunohistochemistry ×100). E In situ hybridization showing the tumor cells are kappa light chain restricted (×100). F In situ hybridization showing the tumor cells are lambda light chain negative (×100). G FISH analysis showing the interphase cells with IGH/MALT1 rearrangement indicated by two fusion signals (juxtaposed green and red signal). The normal IgH and MALT1 loci are represented by the single red and single green signals respectively (×100)

Fig. 2

Immunoglobulin heavy-chain gene rearrangement study—PCR product analyzed by capillary electrophoresis showing a clonal rearrangement. X axis length of amplicon, Y axis intensity of signal