Burkitt t(8;14)(q24;q32) and cryptic deletion in a CLL patient: report of a case and review of literature

A 53-year-old man diagnosed with chronic lymphocytic leukemia (CLL)–small lymphoma following splenectomy was found to have a t(8;14) with an apparent cryptic deletion of the MYC gene. This patientʹs spleen and bone marrow (BM) showed that 93% and ∼70% of the viable cells, respectively, were λ-monoclonal B-cells coexpressing CD5 with CD20, CD19, CD23, CD22, CD38, and low FMC-7. The smear showed a marked increase in small, mature lymphoid cells, with <2% prolymphocytes. The BM karyotype was 46,XY,t(8;14)(q24;q32),−18,+mar[3]/46,XY[27] and FISH analysis with an IGH/MYC green–red dual-fusion signal probe showed an atypical interphase result of one fusion, two green, and one red signal in 70% of the cells. The MYC dual red–green split-apart probe showed the expected t(8;14) pattern in 62% of the cells; however, sequential FISH on a t(8;14) GTG-metaphase showed the single fusion signal on derivative chromosome 8 and only a green signal on der(14) for the IGH/MYC dual-fusion probe and a green signal on der(14), red signal on der(8), and fusion signal on the normal chromosome 8 for the MYC split-apart probe. Thus, the apparently balanced t(8;14) had a cryptic deletion (∼1.6 Mb) between the red and the green regions flanking the MYC gene in the MYC split-apart probe, 128,585,631–130,226,339 bp from 8pter. The rarity of t(8;14) in CLL together with a cryptic deletion that probably includes the MYC gene in our CLL patient persuaded us to explore the clinicopathological role of MYC translocations by comparing disease progression in our patient and in other reported CLL cases.