Acquired EVI1 rearrangement involved in the transformation from 5q- syndrome to pre-B lymphocytic leukemia in a Chinese patient

The anomalous EVI1 rearrangements/t(3;3)(q21;q26) is more frequently found in myelocytic malignancies. 5q- syndrome is a newly defined subtype of myelodysplastic syndrome (MDS) first proposed by the World Health Organization in 2001. Cases of acute lymphocytic leukemia (ALL) with 5q- anomaly or t(3;3)/EVI1 rearrangement have rarely been reported. We report a rare 5q- syndrome case which ultimately transformed to acute lymphocytic leukemia accompanied by a secondary cytogenetic anomaly of t(3;3)(q21;q26) and EVI1 rearrangement around 3 years after the diagnosis of 5q- syndrome. This rare case suggests that the 5q- clone of MDS may originate from a multipotent cell with a capacity to differentiate toward both myeloid and lymphoid lineages. It also indicates that although the t(3;3)/EVI1 rearrangement is mostly related to myelocytic neoplasms, the t(3;3)/EVI1-rearrangement may also play an important role in the development of ALL. The results of the necessary tests must be analyzed sufficiently prior to making a final diagnosis.