Double-hit pancreatic B-lymphoblastic lymphoma with a variant translocation t(2;18)(p11;q21).

ABSTRACT

Double-hit lymphoma is typically categorized as "high-grade B-cell lymphoma, with MYC and BCL2 and/or BCL6 rearrangements", but in infrequent cases in which terminal deoxynucleotidyl transferase (TdT) expression is positive, it is categorized as B-lymphoblastic lymphoma (B-LBL). BCL2 rearrangements are usually caused by t(14;18)(q32;q21); variant translocations are very rare. Here, we describe an unusual case of double-hit pancreatic B-LBL with a variant translocation t(2;18)(p11;q21). A 69-year-old man was admitted because of an abdominal mass. Computed tomography scans demonstrated a diffusely enlarged pancreas and massive ascites. Cell block preparations of ascites cells revealed marked proliferation of blastic lymphoid cells positive for CD19, CD10, CD79a, PAX5, and TdT, indicating a diagnosis of B-LBL. G-banding and spectral karyotyping showed 45,XY,+X,t(2;18)(p11;q21),-4,der(5)t(1;5)(q12;p15),der(6)t(6;21)(q21;q?),t(8;14)(q24;q32),-15. Fluorescence in situ hybridization detected split BCL2 and IGH/MYC fusion signals. Almost all ascites cells were diffusely and strongly positive for MYC and BCL2. The patient died of progressive disease 20 days after admission. To our knowledge, this is the first reported case of MYC and BCL2 double-hit B-LBL with t(2;18)(p11;q21). High coexpression of MYC by t(8;14) and BCL2 by t(2;18) may be implicated in the development of B-LBL. Furthermore, double-hit B-LBL may be associated with a less favorable outcome compared with typical B-LBL.