Mantle cell lymphoma with 8q24 chromosomal abnormalities: a report of 5 cases with blastoid features.

The t(11;14)(q13;q32) resulting in cyclin D1 overexpression is consistently present in mantle cell lymphoma. However secondary chromosomal aberrations are also extremely common. Of these, 8q24 abnormalities associated with the t(11;14) are rare. Over the course of 10 years at M.D. Anderson Cancer Center, we identified five cases of mantle cell lymphoma in which conventional cytogenetic analysis revealed complex karyotypes, including the t(11;14) and 8q24 abnormalities: one with t(8;14)(q24;q32), one with t(2;8)(q13;q24), and three with add(8)(q24). We performed fluorescence in situ hybridization (FISH) studies on all cases. In the case with the t(8;14), IgH/myc fusion signals were identified, and in the case with the t(2;8), split c-myc signals were detected. In the three cases with add(8)(q24), one case had split c-myc signals and two cases had three copies of c-myc. Thus, the c-myc gene was involved in all cases. All five neoplasms had blastoid morphologic features, and four cases, including the cases with the t(8;14) and t(2;8), had leukemic involvement. We conclude that 8q24 abnormalities involving the c-myc gene are uncommon secondary abnormalities that occur in a subset of mantle cell lymphomas. C-myc gene abnormalities are associated with blastoid cytologic features and also may be associated with leukemic involvement.