Clinicopathological features of EBV-positive polymorphic B-cell lymphoproliferative disorders involving central nervous system in people living with HIV.

Aim: To investigate the histomorphological, immunophenotypic and molecular pathological features of Epstein-Barr virus (EBV)-positive polymorphic B-cell lymphoproliferative disorders (LPD) of the central nervous system (CNS) in people living with HIV.

Methods: Seven HIV-positive patients with primary CNS lesions were retrospectively analysed. According to the 5th edition of the WHO Classification of Haematolymphoid Tumours and 2022 International Consensus Classification of mature B-cell lymphomas, these patients were pathologically diagnosed based on their H&E staining, immunohistochemistry, immunoglobulin heavy chain (IGH) clonality analysis, EBV-encoded RNA (EBER) fluorescence in situ hybridisation (FISH) and clinical data.

Results: MRI revealed lesions in the frontal lobe, cerebellar vermis, occipital lobe, temporal lobe, basal ganglia and thalamus, with four patients exhibiting lesions in multiple locations. Histopathological examination revealed polymorphic lymphocytic infiltrates in brain tissue, including lymphocytes, histiocytes, immunoblasts, plasma cells, atypical large B-cell and Hodgkin-Reed-Sternberg-like cells, with B-cell predominantly. Lymphocytic infiltration was mainly perivascular, with focal coagulative necrosis observed in four cases. Immunohistochemistry identified B-cell (CD20+, CD79a+), large B-cell and immunoblasts (CD30+), T-cell (CD3+), histiocytes (CD68+) and plasma cells (CD138+). All cases were positive for BCL-2 and Ki67 (20%-60%+), with three cases positive for EBNA2. All cases were negative for LMP1, HHV8, Bcl-6 and CD15. EBER in situ hybridisation was positive in all cases, and five cases showed IGH clonal rearrangement. FISH testing for IGH breakage recombination was negative in all seven cases.

Conclusion: Accurate diagnosis of EBV-positive polymorphic B-cell LPD in the CNS of HIV patients requires a comprehensive approach including histology, immunophenotyping, molecular testing, and clinical information.