Akademik Veri Yönetim Sistemi
21st Meeting of the European association for Haematopathology, Florence, İtalya, 17 - 22 Eylül 2022, ss.159
Background: Lymphoplasmacytic lymphoma (LPL) a low-grade B cell lymphoproliferative neoplasm, usually involves
bone marrow and less commonly spleen or lymph nodes. The majority of patients have a circulating monoclonal IgM
which has a potential to cause hyper viscosity syndrome (WM). The great majority of LPLs have a pathogenic mutation in
MYD88 (L265P) gene and also could gain additional mutations such as CXCR4, ARID1A and CD79B genes during the
course of the disease. Although, the presence of MYD88 L265P mutation can be sensitive for the diagnosis, it is not
specific for the LPLs. It can also be present in diffuse large B cell lymphomas (DLBCL), rarely in marginal zone lymphoma
(MZL), and chronic lymphocytic leukemia (CLL). The diagnosis of LPLs in some cases can be challenging due to the lack
of specific morphologic and immunophenotypic changes. Hence, the differentiation from other small B cell lymphomas is
usually made by exclusion. Our aim in this study is to analyze the diagnostic and predictive value of NGS based molecular
testing on differential diagnosis of small B cell lymphomas with plasma cell differentiation.
Materials and Methods: In this study, molecular data analyzed by NGS method on Illumina platform with targeted gene
panel of 41 cases with LPL (27), MZL (11) and splenic MZL (3) were retrieved from the department archives. Additional
mutations of various genes are recorded
Results: We analyzed 14 female, 27 male patients with median age of 61 (39-85) years. Out of 27 LPL cases, 24 patients
harbored MYD88 L265P mutation, 1 patient had MYD88 L230N mutation. Two patients with typical clinical features of LPL
were MYD88 wild type. One of them was carrying UBR5 and the other was ARID1A and EP300 mutations. In LPL group,
7 patients with MYD88 mutation had a co-occurrence of CXCR4 mutation, 13 patients had UBR5 mutation, 1 patient had
ARID1A and 1 patient had CD79B mutation. 19 out of 27 LPL patients with MYD88 mutation had high serum IgM levels;
and almost all LPL cases the bone marrow was involved. Twelve patients with LPL received standard chemotherapy and
4 patients have also received ibrutinib. As opposed to LPLs MYD88 mutation was not seen in MZLs and splenic MZLs. In
2/3 patients with splenic MZL had a mutation in the NOTCH2 gene and one of them have had KLF2 mutation as well. Ten
out of 27 patients who have treated with Ibrutinib also received various chemotherapy combinations. These carry
additional mutations on TP53, UBR5, NOTCH2, EZH2 genes. Two of them are treated with Lenalidomide.
Conclusion: Mutation profiling by using NGS platform, with multigene panels is helpful for the differential diagnosis of
small B cell lymphomas with plasma cell differentiation. Additional mutations with MYD88 are important to evaluate since
their impact on predicting the alternative targeted therapies.