Primary central nervous system lymphomas (PCNSLs) are extranodal non-Hodgkin lymphomas confined to the brain, leptomeninges, eyes, or spinal cord without systemic involvement. The main goal of this study is to examine the incorporation of PCNSLs in three distinct "blue books" (WHO Classification of CNS Tumors WHO-CNS5, WHO Classification of Hematopoietic and Lymphoid Tissues, Revised 4th edition WHO-HAEM4R, WHO Classification of Hematolymphoid Tumors, 5th edition beta version WHO-HAEM5-Beta). Fifteen immunocompetent patients diagnosed with PCNSL between 2016 and 2023 were included in this study. WHO-CNS5 and WHO-HAEM4R diagnoses were revised according to the WHO-HAEM5-Beta classification. Fluorescence in situ hybridization (FISH) examination was used to investigate MYC, BCL6, and BCL2 rearrangement in large B-cell lymphomas of immune privileged sites (IP-LBCL) of patients. Of the 15 patients diagnosed with PCNSL, 10 (66.6%) had IP-LBCL. The patients had a mean age of 59.43 years, and 9 (60%) were female. The cerebral hemisphere was the most frequent tumor site. No rearrangements were detected in seven cases of IP-LBCL by FISH analysis. No significant correlations were found between the percentage increase in BCL2, BCL6, C-MYC, or MUM-1 expression and overall survival. However, as the percentage of BCL2 expression increased, there was a significant increase in BCL6 expression. PCNSL is an extranodal non-Hodgkin lymphoma that typically affects older individuals and has a poor prognosis and challenging treatment. In this study, we re-evaluated our cases diagnosed with PCNSL using the three "blue books" and revised the diagnoses according to WHO HAEM5-Beta. The absence of MYC and BCL2 rearrangements supports the diagnosis of IP-LBCL, as determined by FISH analysis.
Şahin et al. (Thu,) studied this question.