A 50-year-old man presented with an ileocecal tumor and a large amount of ascites. Lymphoma cells obtained from the ascitic fluid were CD10(+), CD20(+), CD38(+), HLA-DR(+), BCL6(-), MUM1/IRF4(+), BCL2(+), and immunoglobulin µ/γ(+). The karyotype determined by G-banding and spectral karyotyping was 46, XY, der(3)t(1;3)(q12;p12), -4, +7, t(8;14)(q24;q32), t(12;14)(q24;q32), der(17)t(4;17)(q21;p11). Fluorescence in situ hybridization disclosed that 93% of interphase cells were positive for the c-MYC and immunoglobulin heavy chain gene fusion. The patient was treated with intensive chemo-immunotherapy, resulting in a complete response. The t(8;14)-t(12;14) double-hit may have generated molecular abnormalities analogous to those of a previously cloned three-way translocation t(8;12;14).