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A subset of low-grade B cell lymphomas with a follicular growth pattern but without a BCL2 translocation shows features suggestive of nodal marginal zone lymphoma.

van den Brand M, Balagué O, van Cleef PH, Groenen PJ, Hebeda KM, de Jong D, van Krieken JH - J Hematop (2015)

Bottom Line: 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 a BCL2 translocation actually represents NMZL.This is at present difficult to prove, because no gold standard is available to differentiate between NMZL and FL without a BCL2 rearrangement, so further investigations are needed.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Radboud University Medical Center, box 9101, 6500 HB Nijmegen, The Netherlands.

ABSTRACT

In our consultation practice, it was noted that many cases that were considered to represent follicular lymphoma (FL) without a BCL2 translocation 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 a BCL2 rearrangement 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 a BCL2 rearrangement, assigning them to one of five categories ranging from "certain FL" to "certain NMZL." Highly recurrent morphological features were noted in the lymphomas without a BCL2 rearrangement, 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 a BCL2 rearrangement, whereas all 12 cases assigned to the category of most likely NMZL or certain NMZL had no BCL2 break. 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 a BCL2 translocation actually represents NMZL. This is at present difficult to prove, because no gold standard is available to differentiate between NMZL and FL without a BCL2 rearrangement, so further investigations are needed.

No MeSH data available.


Related in: MedlinePlus

Morphological features of cases without BCL2 translocation. a–f Lymph node showing completely effaced architecture with a nodular appearance on low power (a). On medium power (b), residual follicles are seen which are BCL2 negative (c) and show a high proliferative index (d). CD10 (e) is expressed not only in the residual follicles but also in the surrounding neoplastic cells. BCL2 staining shows blasts without BCL2 expression at high power (f). This case was classified as “certainly NMZL” based on morphological features. g–j Another lymphoma with nodular architecture on high power (g). BCL2 immunohistochemistry shows poorly defined areas with BCL2-negative cells (h). In these areas, a high proliferative index is present, indicated by frequent Ki-67-positive cells (i). BCL6 shows diffuse positivity with heterogeneous intensity (j). This case was classified as “most likely NMZL” based on morphological features
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Fig1: Morphological features of cases without BCL2 translocation. a–f Lymph node showing completely effaced architecture with a nodular appearance on low power (a). On medium power (b), residual follicles are seen which are BCL2 negative (c) and show a high proliferative index (d). CD10 (e) is expressed not only in the residual follicles but also in the surrounding neoplastic cells. BCL2 staining shows blasts without BCL2 expression at high power (f). This case was classified as “certainly NMZL” based on morphological features. g–j Another lymphoma with nodular architecture on high power (g). BCL2 immunohistochemistry shows poorly defined areas with BCL2-negative cells (h). In these areas, a high proliferative index is present, indicated by frequent Ki-67-positive cells (i). BCL6 shows diffuse positivity with heterogeneous intensity (j). This case was classified as “most likely NMZL” based on morphological features

Mentions: In a first effort, the morphological features in the translocation-negative group were evaluated. The following features were observed to be highly recurrent (Fig. 1): (1) effaced architecture of the lymph node by a small B cell proliferation with a follicular, marginal zone, or diffuse growth pattern; (2) centrocytic or “CLL-like” small cell morphology with intermingled centroblasts; (3) an immunophenotype of a mature B cell (CD20 and CD79a positive) with BCL2 positivity and lacking expression of cyclin D1 and CD5; (4) The cases with a follicular/ nodular growth pattern showed follicular colonization; the presence of both neoplastic and reactive cells in a follicle. For the assessment of follicular colonization, BCL2 and Ki67 immunohistochemistry were carefully evaluated. For BCL2, positive cells (the colonizing lymphoma cells) could be recognized among negative cells (the pre-existent cells) at high power. For Ki67, clusters of highly proliferative cells characterized follicles being colonized, whereas truly neoplastic follicles were characterized by a relatively low proliferative index. Expression of CD10 in the BCL2-positive cells was observed only rarely (in 5 out of 21 cases), with mostly weak staining. In 3 out of 16 cases, weak BCL6 expression was observed in BCL2-positive cells.Fig. 1


A subset of low-grade B cell lymphomas with a follicular growth pattern but without a BCL2 translocation shows features suggestive of nodal marginal zone lymphoma.

van den Brand M, Balagué O, van Cleef PH, Groenen PJ, Hebeda KM, de Jong D, van Krieken JH - J Hematop (2015)

Morphological features of cases without BCL2 translocation. a–f Lymph node showing completely effaced architecture with a nodular appearance on low power (a). On medium power (b), residual follicles are seen which are BCL2 negative (c) and show a high proliferative index (d). CD10 (e) is expressed not only in the residual follicles but also in the surrounding neoplastic cells. BCL2 staining shows blasts without BCL2 expression at high power (f). This case was classified as “certainly NMZL” based on morphological features. g–j Another lymphoma with nodular architecture on high power (g). BCL2 immunohistochemistry shows poorly defined areas with BCL2-negative cells (h). In these areas, a high proliferative index is present, indicated by frequent Ki-67-positive cells (i). BCL6 shows diffuse positivity with heterogeneous intensity (j). This case was classified as “most likely NMZL” based on morphological features
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig1: Morphological features of cases without BCL2 translocation. a–f Lymph node showing completely effaced architecture with a nodular appearance on low power (a). On medium power (b), residual follicles are seen which are BCL2 negative (c) and show a high proliferative index (d). CD10 (e) is expressed not only in the residual follicles but also in the surrounding neoplastic cells. BCL2 staining shows blasts without BCL2 expression at high power (f). This case was classified as “certainly NMZL” based on morphological features. g–j Another lymphoma with nodular architecture on high power (g). BCL2 immunohistochemistry shows poorly defined areas with BCL2-negative cells (h). In these areas, a high proliferative index is present, indicated by frequent Ki-67-positive cells (i). BCL6 shows diffuse positivity with heterogeneous intensity (j). This case was classified as “most likely NMZL” based on morphological features
Mentions: In a first effort, the morphological features in the translocation-negative group were evaluated. The following features were observed to be highly recurrent (Fig. 1): (1) effaced architecture of the lymph node by a small B cell proliferation with a follicular, marginal zone, or diffuse growth pattern; (2) centrocytic or “CLL-like” small cell morphology with intermingled centroblasts; (3) an immunophenotype of a mature B cell (CD20 and CD79a positive) with BCL2 positivity and lacking expression of cyclin D1 and CD5; (4) The cases with a follicular/ nodular growth pattern showed follicular colonization; the presence of both neoplastic and reactive cells in a follicle. For the assessment of follicular colonization, BCL2 and Ki67 immunohistochemistry were carefully evaluated. For BCL2, positive cells (the colonizing lymphoma cells) could be recognized among negative cells (the pre-existent cells) at high power. For Ki67, clusters of highly proliferative cells characterized follicles being colonized, whereas truly neoplastic follicles were characterized by a relatively low proliferative index. Expression of CD10 in the BCL2-positive cells was observed only rarely (in 5 out of 21 cases), with mostly weak staining. In 3 out of 16 cases, weak BCL6 expression was observed in BCL2-positive cells.Fig. 1

Bottom Line: 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 a BCL2 translocation actually represents NMZL.This is at present difficult to prove, because no gold standard is available to differentiate between NMZL and FL without a BCL2 rearrangement, so further investigations are needed.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Radboud University Medical Center, box 9101, 6500 HB Nijmegen, The Netherlands.

ABSTRACT

In our consultation practice, it was noted that many cases that were considered to represent follicular lymphoma (FL) without a BCL2 translocation 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 a BCL2 rearrangement 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 a BCL2 rearrangement, assigning them to one of five categories ranging from "certain FL" to "certain NMZL." Highly recurrent morphological features were noted in the lymphomas without a BCL2 rearrangement, 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 a BCL2 rearrangement, whereas all 12 cases assigned to the category of most likely NMZL or certain NMZL had no BCL2 break. 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 a BCL2 translocation actually represents NMZL. This is at present difficult to prove, because no gold standard is available to differentiate between NMZL and FL without a BCL2 rearrangement, so further investigations are needed.

No MeSH data available.


Related in: MedlinePlus