Clinicopathologic and genetic profile of intracranial marginal zone lymphoma: a primary low-grade CNS lymphoma that mimics meningioma.
OBJECTIVE
Although rare overall, marginal zone B-cell lymphoma (MZBCL) is the most common primary low-grade CNS lymphoma reported in the literature. The aim of this study is to elucidate the biology and genetic features of this unusual tumor.


METHODS
Fifteen CNS MZBCLs were studied clinically, pathologically, and genetically, including fluorescent in situ hybridization analyses with commercially available MALT1 and IgH break-apart and centromere 3, 7, 12, and 18 probes.


RESULTS
CNS MZBCLs preferentially affect middle-aged women (female-to-male ratio, 4:1), with 93% presenting as dural-based masses mimicking meningioma. Ten patients with 1 to 7.6 years of follow-up after diagnosis showed no evidence of disease after radiation and/or chemotherapy. Like MZBCLs outside of the CNS, they consisted of CD20+, CD3- small B lymphocytes with varying degrees of plasmacytic differentiation and predominantly kappa light-chain restriction (78%). Lymphoid follicles with follicular colonization were seen in three patients and deposition of amyloid was noted in samples from two patients, one of which was tumefactive. Neither Bcl-6 protein nor Epstein-Barr virus-encoded RNA was expressed. Trisomy 3 was detected in six of 12 patients, with no rearrangements of MALT1 or IgH and no trisomies of 7, 12, or 18 detected.


CONCLUSIONS
Our data suggest that intracranial MZBCL is an indolent primary CNS lymphoma that typically presents as a meningioma-like dural-based mass. Trisomy 3, but not MALT1 or IgH translocation, is a common genetic abnormality that may contribute to the pathogenesis of this CNS lymphoma.
Tu
Pang-Hsien
PH
Division of Neuropathology and Section of Hematopathology, Campus Box 8118, Washington University School of Medicine, St Louis, MO 63110-1093, USA. btu@path.wustl.edu
Giannini
Caterina
C
Judkins
Alexander R
AR
Schwalb
Jason M
JM
Burack
Richard
R
O'Neill
Brian P
BP
Yachnis
Anthony T
AT
Burger
Peter C
PC
Scheithauer
Bernd W
BW
Perry
Arie
A
D000328:Adult; D000368:Aged; D016543:Central Nervous System Neoplasms / Q000235:genetics* / Q000473:pathology*; D002893:Chromosomes, Human, Pair 3; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics* / Q000473:pathology*; D008297:Male; D008579:Meningioma / Q000473:pathology; D008875:Middle Aged; D014178:Translocation, Genetic; D014314:Trisomy