Lymphoplasmacytic lymphoma (LPL) is a B-cell lymphoproliferative disorder typically involving the bone marrow with infiltration by small lymphocytes and plasma cells. Studies have identified MYD88 L26 Show more
Lymphoplasmacytic lymphoma (LPL) is a B-cell lymphoproliferative disorder typically involving the bone marrow with infiltration by small lymphocytes and plasma cells. Studies have identified MYD88 L265P mutation as a diagnostic marker to distinguish LPL from other small B-cell lymphomas. Detection rates for this mutation have varied depending on the analytic methodology, with previous data suggesting that routine next-generation sequencing (NGS) does not demonstrate the required sensitivity to reliably detect MYD88 L265P. NGS has become part of routine clinical testing because it allows detection of variants across multiple genes. To study the utility of NGS in the detection of MYD88 L265P, we performed droplet digital PCR (ddPCR) and routine NGS on a cohort of 34 cases of lymphoid neoplasms (22 LPL, 4 CLL, 1 MCL, 1 MGUS, 2 plasma cell myeloma, and 4 negative bone marrow cases). We utilized manual review and BAMtools to assess MYD88 L265P in NGS cases. Limit of detection for ddPCR was determined to be 0.4 % variant allele frequency (VAF) with 10 ng DNA input. MYD88 L265P VAF detection by NGS and ddPCR was comparable down to 0.5 % VAF (R Show less
T(14;19) is an unusual but distinct genomic alteration reported in low-grade B-cell lymphomas. This structural rearrangement places BCL3 in juxtaposition with IGH inducing proliferation and has been f Show more
T(14;19) is an unusual but distinct genomic alteration reported in low-grade B-cell lymphomas. This structural rearrangement places BCL3 in juxtaposition with IGH inducing proliferation and has been found in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), marginal zone lymphoma (MZL), and other low-grade B-cell lymphomas. While there are some case series describing this in the context of other cytogenetic alterations, there are limited clinical cases examined from a molecular perspective. We herein describe a case of a low-grade B-cell lymphoma with t(14;19) resulting in IGH::BCL3 fusion on which we performed whole exome sequencing to investigate genetic variants that could contribute to its pathogenesis. We found pathogenic alterations including a variant in CXCR4 which has been shown to be recurrently mutated in different low-grade B-cell lymphomas including lymphoplasmacytic lymphoma (LPL) and MZL. We describe this interesting case in the context of its genomic findings and how it contributes to the literature as a whole. Show less