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NI Feature: Pathological Panorama ORIGINAL ARTICLE
Clinicopathological correlates of primary central nervous system lymphoma: Experience from a tertiary care center in South India Bimal Patel, Geeta Chacko, Sheila Nair, Jamie Anandan, Ari G. Chacko1, Vedantam Rajshekhar1, Mazda Turel1 Department of General Pathology, Section of Neuropathology, 1Department of Neurological Sciences, Section of Neurosurgery, Christian Medical College, Vellore, Tamil Nadu, India
ABSTRACT Background: Primary central nervous system lymphomas (PCNSL) constitute a rare group of extranodal non-Hodgkin’s lymphomas (NHLs). Aim: To study the clinical and immunophenotypic profile of patients with a PCNSL who presented between the years 2000 and 2013 in a tertiary care center in South India. Materials and Methods: This was a retrospective study. Demographic and clinical data were obtained from the clinical case records. Inclusion criteria: Cases of PCNSL involving brain. Exclusion criteria: Cases of PCNSL involving the spinal cord, meninges and orbit as well as intravascular large B-cell lymphoma, lymphomas with evidence of systemic disease or secondary lymphomas. Archived slides and tissue blocks were retrieved. All cases had hematoxylin and eosin stained sections and immunohistochemistry for CD20, CD3, and MIB-1. Additional immunohistochemistry was performed for CD10, BCL6, and MUM1 on paraffin blocks with sufficient tissue. Results: There were a total of 73 cases with the mean age of presentation being 45.9 years (range 8–71 years) and with a male predominance (male: female (M:F) = 2.3:1). Headache was the commonest presenting complaint. The mean duration of symptoms was 10.6 weeks. All patients were immunocompetent. Most tumors were supratentorial in location. Out of 73 cases, 70 presented with a diffuse large B‑cell lymphoma (DLBCL), two with a Burkitt’s lymphoma, and one with a lymphomatoid granulomatosis. Only 51 of the DLBCL cases had sufficient tissue for additional studies. Non-germinal center was the most common phenotype seen in 65.7% (33/51) of cases. Germinal center B-cell (GCB) phenotype was seen in 18/51 cases (34.3%). Conclusion: DLBCL constituted the majority of PCNSLs and although non-germinal center was the predominant phenotype, more than a third of the cases were of the GCB phenotype. As the germinal center phenotype is known to have a better prognosis, further studies to explore its relevance in the Asian population are indicated. Key words: Diffuse large B-cell lymphoma; immunophenotyping; primary CNS lymphoma
Introduction
Access this article online Website: www.neurologyindia.com DOI: 10.4103/0028-3886.152658 PMID: xxxxx
Quick Response Code
Primary central nervous system lymphomas (PCNSLs) are rare, extranodal, malignant lymphomas arising within the brain, eyes, leptomeninges, or spinal cord in the absence of systemic lymphoma at the time of diagnosis. In the Western world, the incidence of PCNSL is 3–4% of all non-Hodgkin’s lymphomas (NHLs),[1] whereas in India, the incidence has been reported
Address for correspondence: Dr. Geeta Chacko, Section of Neuropathology, Department of Pathology, Christian Medical College, Vellore ‑ 632 004, Tamil Nadu, India. E‑mail: [email protected]
Neurology India / January 2015 / Volume 63 / Issue 1
77
[Downloaded free from http://www.neurologyindia.com on Thursday, March 05, 2015, IP: 202.177.173.189] || Click here to download free Android application for this journal Patel, et al.: Clinicopathological correlates of primary central nervous system lymphoma
to range from 0.95 to 1.4%.[2] Although PCNSL has a strong association with acquired immunodeficiency syndrome (AIDS), and human immunodeficiency virus (HIV) infection carries a 3,600-fold increased risk of developing the disease compared to general population,[3] recent epidemiologic data suggest a decrease in the incidence of PCNSL, particularly among young patients suffering from AIDS. Amongst immunocompetent patients, a higher incidence is seen in older patients (> 60 years), and the overall improvement in longevity has been cited as a reason for this increasing incidence with age.[1,4]
Inclusion criteria: Only lymphomas involving the cerebral parenchyma were included in this study. Cases of PCNSL involving the spinal cord, meninges and the orbit and those with intravascular large B-cell lymphoma, lymphomas with evidence of systemic disease or secondary lymphomas were excluded.
According to the World Health Organization (WHO) classification, most of the primary CNS lymphomas (> 95%) are diffuse large B-cell lymphomas (DLBCL); however, WHO does not identify PCNSL as a separate entity due to morphological similarity to nodal DLBCLs.[5] The exact pathogenesis of PCNSL is unclear.[6] Among systemic DLBCLs, gene expression profiling studies identified two subgroups (germinal center B-cell type (GCB) and activated B-cell type [ABC]) indicative of different stages of B-cell differentiation.[7] The two subgroups differ not only in the immunophenotypic profile but also in aggressiveness, prognosis, and treatment, with the GCB profile showing a significantly better outcome than those with the ABC profile.[7] Several of the antigens that are differentially expressed in germinal center and post-GCBs can be identified by immunohistochemical analysis on paraffin sections. For example, CD10 and BCL-6 are markers for GCB,[8,9] MUM-1 is a marker for late germinal center/early post-GCB,[10,11] and CD138 and VS38 are markers for plasmacytic and/or postgerminal center differentiation.[12,13] Several algorithms for subtyping have been described in the literature.[14-21] Of the various algorithms proposed for subtyping, Hans algorithm appears to be the most popular one.[22-31] Expression of CD138 in PCNSL is rare;[22,24,29,32] and hence in the context of PCNSL, CD138 has not been employed by several studies. The prognosis of PCNSL is poor with a 5-year overall survival (OS) rate of approximately 30% even for patients receiving best of treatment protocols.[33-36] It is yet unclear whether the poor outcome is attributable to the fact that the tumor is located in the CNS or reflects an exceptionally aggressive biological behavior of tumor cells in the CNS.
Tumor specimen Paraffin blocks of archived biopsies were retrieved from the Department of Pathology of a tertiary care hospital in South India. The tumor specimens had been obtained by open or stereotactic procedure for diagnosis. The WHO classification of lymphoid and hematological malignancies was used for the histological diagnosis of PCNSL. Cases were selected on the basis of the availability of paraffin-embedded tumor tissues.
The aim of this study was to determine the clinical profile and immunophenotype of PCNSL in patients who presented in this institution between the years 2000 and 2013.
Materials and Methods Patients This was a retrospective study. Clinical data of the patients were obtained from the hospital database. 78
All standard protocols were followed for the diagnosis and treatment with informed consent obtained from all these patients (Approval for the present study was obtained from the Institutional Review Board).
Histology and immunohistochemical analysis Five micron (hematoxylin and eosin stained) sections of all the cases were reviewed. CD20, CD3, and MIB-1 immunostaining had been done at the time of primary diagnosis of PCNSLs using the following clones CD20 (Clone L26, Monoclonal mouse anti-human CD20cy, Dako), CD3 (Polyclonal rabbit anti-human CD3, Dako), and MIB-1 (Clone MIB-1, Monoclonal mouse anti-human Ki-67 antigen, Dako). Immunostaining was performed in the Ventana Autostainer using the Envision method. After a review of cases, a panel of further immunohistochemical studies was done on paraffin-embedded tissue sections. Sections were cut at 4-µm thickness and deparaffinized. Antigen retrieval was carried out by pressure cooking method. Sections were then incubated with the working dilution of each antibody raised against the following antigens: CD10 (GCB marker; liquid mouse monoclonal antibody, Novocastra, Clone 56C6, dilution 1:100), BCL-6 (GCB marker; liquid mouse monoclonal antibody, Novocastra, Clone LN22, dilution 1:100); and MUM-1 (non-GCB marker; monoclonal mouse anti-human MUM1 protein, Dako, dilution 1:100). For CD10, BCL-6 and MUM-1, positive expression was defined as positive staining in >30% of cells.[34] For CD10, only membrane and cytoplasmic staining were considered positive, and in the case of BCL-6 and MUM-1, only diffuse or granular nuclear staining was considered positive; CD10, BCL-6, and MUM-1 expression results were used to subclassify DLBCL cases into GCB or non-GCB subgroups as described below.
Neurology India / January 2015 / Volume 63 / Issue 1
[Downloaded free from http://www.neurologyindia.com on Thursday, March 05, 2015, IP: 202.177.173.189] || Click here to download free Android application for this journal Patel, et al.: Clinicopathological correlates of primary central nervous system lymphoma
Classification of DLBCL into GCB and non-GCB For classification of DLBCL into two immunophenotypic subgroups, Hans[14] algorithm [Figure 1] was used in the present study. Hans algorithm uses CD10, BCL-6, and MUM1 immunoexpression with following two subsets of markers expression favoring GCB subtype: (CD10 (+), BCL6 (+), MUM1 (-)) and (CD10 (−), BCL6 (+), MUM-1 (−)); while (CD10 (−), BCL6 (+), MUM-1 (+)) and (CD10 (−), BCL6 (-), MUM-1 (+)) subsets favoring non-GCB subtype.
Results A total of 73 cases of PCNSL involving the cerebral parenchyma were identified in the study period (2000–2013). A progressive increase in the hospital-based incidence of CNS lymphoma was noted during the study period, with a gradual increase from 0.09% of all biopsies received at the neuropathology laboratory for examination at the beginning of the study period to 0.38% at the end. There were four pediatric patients with a PCNSL (mean age: 9.7 years). The overall mean age was 46 years (range: 8–71 years) and twice as many males were affected (male: female (M:F) ratio = 2.3:1). All the patients were immunocompetent. The mean duration of symptoms was 10.6 weeks (range:
NI Feature: Pathological Panorama ORIGINAL ARTICLE
Clinicopathological correlates of primary central nervous system lymphoma: Experience from a tertiary care center in South India Bimal Patel, Geeta Chacko, Sheila Nair, Jamie Anandan, Ari G. Chacko1, Vedantam Rajshekhar1, Mazda Turel1 Department of General Pathology, Section of Neuropathology, 1Department of Neurological Sciences, Section of Neurosurgery, Christian Medical College, Vellore, Tamil Nadu, India
ABSTRACT Background: Primary central nervous system lymphomas (PCNSL) constitute a rare group of extranodal non-Hodgkin’s lymphomas (NHLs). Aim: To study the clinical and immunophenotypic profile of patients with a PCNSL who presented between the years 2000 and 2013 in a tertiary care center in South India. Materials and Methods: This was a retrospective study. Demographic and clinical data were obtained from the clinical case records. Inclusion criteria: Cases of PCNSL involving brain. Exclusion criteria: Cases of PCNSL involving the spinal cord, meninges and orbit as well as intravascular large B-cell lymphoma, lymphomas with evidence of systemic disease or secondary lymphomas. Archived slides and tissue blocks were retrieved. All cases had hematoxylin and eosin stained sections and immunohistochemistry for CD20, CD3, and MIB-1. Additional immunohistochemistry was performed for CD10, BCL6, and MUM1 on paraffin blocks with sufficient tissue. Results: There were a total of 73 cases with the mean age of presentation being 45.9 years (range 8–71 years) and with a male predominance (male: female (M:F) = 2.3:1). Headache was the commonest presenting complaint. The mean duration of symptoms was 10.6 weeks. All patients were immunocompetent. Most tumors were supratentorial in location. Out of 73 cases, 70 presented with a diffuse large B‑cell lymphoma (DLBCL), two with a Burkitt’s lymphoma, and one with a lymphomatoid granulomatosis. Only 51 of the DLBCL cases had sufficient tissue for additional studies. Non-germinal center was the most common phenotype seen in 65.7% (33/51) of cases. Germinal center B-cell (GCB) phenotype was seen in 18/51 cases (34.3%). Conclusion: DLBCL constituted the majority of PCNSLs and although non-germinal center was the predominant phenotype, more than a third of the cases were of the GCB phenotype. As the germinal center phenotype is known to have a better prognosis, further studies to explore its relevance in the Asian population are indicated. Key words: Diffuse large B-cell lymphoma; immunophenotyping; primary CNS lymphoma
Introduction
Access this article online Website: www.neurologyindia.com DOI: 10.4103/0028-3886.152658 PMID: xxxxx
Quick Response Code
Primary central nervous system lymphomas (PCNSLs) are rare, extranodal, malignant lymphomas arising within the brain, eyes, leptomeninges, or spinal cord in the absence of systemic lymphoma at the time of diagnosis. In the Western world, the incidence of PCNSL is 3–4% of all non-Hodgkin’s lymphomas (NHLs),[1] whereas in India, the incidence has been reported
Address for correspondence: Dr. Geeta Chacko, Section of Neuropathology, Department of Pathology, Christian Medical College, Vellore ‑ 632 004, Tamil Nadu, India. E‑mail: [email protected]
Neurology India / January 2015 / Volume 63 / Issue 1
77
[Downloaded free from http://www.neurologyindia.com on Thursday, March 05, 2015, IP: 202.177.173.189] || Click here to download free Android application for this journal Patel, et al.: Clinicopathological correlates of primary central nervous system lymphoma
to range from 0.95 to 1.4%.[2] Although PCNSL has a strong association with acquired immunodeficiency syndrome (AIDS), and human immunodeficiency virus (HIV) infection carries a 3,600-fold increased risk of developing the disease compared to general population,[3] recent epidemiologic data suggest a decrease in the incidence of PCNSL, particularly among young patients suffering from AIDS. Amongst immunocompetent patients, a higher incidence is seen in older patients (> 60 years), and the overall improvement in longevity has been cited as a reason for this increasing incidence with age.[1,4]
Inclusion criteria: Only lymphomas involving the cerebral parenchyma were included in this study. Cases of PCNSL involving the spinal cord, meninges and the orbit and those with intravascular large B-cell lymphoma, lymphomas with evidence of systemic disease or secondary lymphomas were excluded.
According to the World Health Organization (WHO) classification, most of the primary CNS lymphomas (> 95%) are diffuse large B-cell lymphomas (DLBCL); however, WHO does not identify PCNSL as a separate entity due to morphological similarity to nodal DLBCLs.[5] The exact pathogenesis of PCNSL is unclear.[6] Among systemic DLBCLs, gene expression profiling studies identified two subgroups (germinal center B-cell type (GCB) and activated B-cell type [ABC]) indicative of different stages of B-cell differentiation.[7] The two subgroups differ not only in the immunophenotypic profile but also in aggressiveness, prognosis, and treatment, with the GCB profile showing a significantly better outcome than those with the ABC profile.[7] Several of the antigens that are differentially expressed in germinal center and post-GCBs can be identified by immunohistochemical analysis on paraffin sections. For example, CD10 and BCL-6 are markers for GCB,[8,9] MUM-1 is a marker for late germinal center/early post-GCB,[10,11] and CD138 and VS38 are markers for plasmacytic and/or postgerminal center differentiation.[12,13] Several algorithms for subtyping have been described in the literature.[14-21] Of the various algorithms proposed for subtyping, Hans algorithm appears to be the most popular one.[22-31] Expression of CD138 in PCNSL is rare;[22,24,29,32] and hence in the context of PCNSL, CD138 has not been employed by several studies. The prognosis of PCNSL is poor with a 5-year overall survival (OS) rate of approximately 30% even for patients receiving best of treatment protocols.[33-36] It is yet unclear whether the poor outcome is attributable to the fact that the tumor is located in the CNS or reflects an exceptionally aggressive biological behavior of tumor cells in the CNS.
Tumor specimen Paraffin blocks of archived biopsies were retrieved from the Department of Pathology of a tertiary care hospital in South India. The tumor specimens had been obtained by open or stereotactic procedure for diagnosis. The WHO classification of lymphoid and hematological malignancies was used for the histological diagnosis of PCNSL. Cases were selected on the basis of the availability of paraffin-embedded tumor tissues.
The aim of this study was to determine the clinical profile and immunophenotype of PCNSL in patients who presented in this institution between the years 2000 and 2013.
Materials and Methods Patients This was a retrospective study. Clinical data of the patients were obtained from the hospital database. 78
All standard protocols were followed for the diagnosis and treatment with informed consent obtained from all these patients (Approval for the present study was obtained from the Institutional Review Board).
Histology and immunohistochemical analysis Five micron (hematoxylin and eosin stained) sections of all the cases were reviewed. CD20, CD3, and MIB-1 immunostaining had been done at the time of primary diagnosis of PCNSLs using the following clones CD20 (Clone L26, Monoclonal mouse anti-human CD20cy, Dako), CD3 (Polyclonal rabbit anti-human CD3, Dako), and MIB-1 (Clone MIB-1, Monoclonal mouse anti-human Ki-67 antigen, Dako). Immunostaining was performed in the Ventana Autostainer using the Envision method. After a review of cases, a panel of further immunohistochemical studies was done on paraffin-embedded tissue sections. Sections were cut at 4-µm thickness and deparaffinized. Antigen retrieval was carried out by pressure cooking method. Sections were then incubated with the working dilution of each antibody raised against the following antigens: CD10 (GCB marker; liquid mouse monoclonal antibody, Novocastra, Clone 56C6, dilution 1:100), BCL-6 (GCB marker; liquid mouse monoclonal antibody, Novocastra, Clone LN22, dilution 1:100); and MUM-1 (non-GCB marker; monoclonal mouse anti-human MUM1 protein, Dako, dilution 1:100). For CD10, BCL-6 and MUM-1, positive expression was defined as positive staining in >30% of cells.[34] For CD10, only membrane and cytoplasmic staining were considered positive, and in the case of BCL-6 and MUM-1, only diffuse or granular nuclear staining was considered positive; CD10, BCL-6, and MUM-1 expression results were used to subclassify DLBCL cases into GCB or non-GCB subgroups as described below.
Neurology India / January 2015 / Volume 63 / Issue 1
[Downloaded free from http://www.neurologyindia.com on Thursday, March 05, 2015, IP: 202.177.173.189] || Click here to download free Android application for this journal Patel, et al.: Clinicopathological correlates of primary central nervous system lymphoma
Classification of DLBCL into GCB and non-GCB For classification of DLBCL into two immunophenotypic subgroups, Hans[14] algorithm [Figure 1] was used in the present study. Hans algorithm uses CD10, BCL-6, and MUM1 immunoexpression with following two subsets of markers expression favoring GCB subtype: (CD10 (+), BCL6 (+), MUM1 (-)) and (CD10 (−), BCL6 (+), MUM-1 (−)); while (CD10 (−), BCL6 (+), MUM-1 (+)) and (CD10 (−), BCL6 (-), MUM-1 (+)) subsets favoring non-GCB subtype.
Results A total of 73 cases of PCNSL involving the cerebral parenchyma were identified in the study period (2000–2013). A progressive increase in the hospital-based incidence of CNS lymphoma was noted during the study period, with a gradual increase from 0.09% of all biopsies received at the neuropathology laboratory for examination at the beginning of the study period to 0.38% at the end. There were four pediatric patients with a PCNSL (mean age: 9.7 years). The overall mean age was 46 years (range: 8–71 years) and twice as many males were affected (male: female (M:F) ratio = 2.3:1). All the patients were immunocompetent. The mean duration of symptoms was 10.6 weeks (range:
