Clinicopathological correlates of primary central nervous system lymphoma: Experience from a tertiary care center in South India

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.