Abstract
Here, we describe the case of a female patient who presented with B-cell lymphoma involving the central nervous system and bone marrow (BM). Although the patient initially responded to chemotherapy, she relapsed shortly afterwards, and her lymphoma spread into the peripheral blood (PB), BM, and meninges. The morphology of the lymphoma cells detected in her BM and cerebrospinal fluid (CSF) at presentation and those in her PB/BM and CSF at relapse varied (in terms of their size, cytoplasmic basophilia, and vacuolization), and they expressed reduced levels of CD20, human leukocyte antigen-DR, and surface immunoglobulins. However, high-grade lymphoma cell cytomorphology is not necessarily associated with an aberrant immunophenotype. Fluorescence in situ hybridization (FISH) of the interphase nuclei of the lymphoma cells revealed both BCL2-immunoglobulin heavy chain (IGH) and MYCIGH fusion genes, except in the initial BM lymphoma cells, which only carried the BCL2-IGH fusion gene, suggesting that this case represents a MYC-BCL2 double-hit lymphoma (DHL) that transformed from an indolent form of lymphoma carrying the BCL2-IGH fusion gene. G-banded karyotyping of the cell line established from the PB lymphoma cells cytogenetically confirmed the presence of both t(8;14)(q24;q32) and t(14;18)(q32;q21). It was noted that increased CD38 expression was associated with the acquisition of t(8;14)(q24;q32)/MYC-IGH, disease progression, and in vitro proliferation. We propose that serial immunophenotypic examinations of lymphoma cells and FISH studies should be performed during the course of cases of lymphoma that are refractory to standard chemotherapy and exhibit evidence of DHL.
