title: A subset of low-grade B cell lymphomas with a follicular growth pattern but without aBCL2translocation shows features suggestive of nodal marginal zone lymphoma.
abstract: In our consultation practice, it was noted that many cases that were considered to represent follicular lymphoma (FL) without aBCL2translocation were ultimately classified as nodal marginal zone lymphoma (NMZL). This study set out to define recurrent morphological features of these cases. Thirty-three low-grade B cell lymphomas without aBCL2rearrangement were studied for recurrent morphological features. These features were then applied on 20 randomly selected cases to verify if these criteria are able to distinguish between lymphomas with and without aBCL2rearrangement, assigning them to one of five categories ranging from "certain FL" to "certain NMZL." Highly recurrent morphological features were noted in the lymphomas without aBCL2rearrangement, which were strongly overlapping with the morphological features of NMZL. All six cases that were assigned to the category of certainly FL or most likely FL indeed harbored aBCL2rearrangement, whereas all 12 cases assigned to the category of most likely NMZL or certain NMZL had noBCL2break. Of the two cases in the ambiguous category, one had received a final diagnosis of FL and the other of NMZL. This study raises the hypothesis that a subset of low-grade B cell lymphomas with a follicular growth pattern but without aBCL2translocation actually represents NMZL. This is at present difficult to prove, because no gold standard is available to differentiate between NMZL and FL without aBCL2rearrangement, so further investigations are needed.
authors.affiliation: Department of Pathology, Radboud University Medical Center, box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Michiel
authors.initials: M
authors.lastname: van den Brand
authors.affiliation: Hematopathology Section, Laboratory of Pathology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: Balagué
authors.affiliation: Department of Pathology, Radboud University Medical Center, box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Patricia H J
authors.initials: PH
authors.lastname: van Cleef
authors.affiliation: Department of Pathology, Radboud University Medical Center, box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Patricia J T A
authors.initials: PJ
authors.lastname: Groenen
authors.affiliation: Department of Pathology, Radboud University Medical Center, box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Konnie M
authors.initials: KM
authors.lastname: Hebeda
authors.affiliation: Department of Pathology, VU Medical Centre, Amsterdam, The Netherlands.
authors.forename: Daphne
authors.initials: D
authors.lastname: de Jong
authors.affiliation: Department of Pathology, Radboud University Medical Center, box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: J Han J M
authors.initials: JH
authors.lastname: van Krieken
keywords: BCL2; Follicular lymphoma; Low-grade B cell lymphoma; Nodal marginal zone lymphoma