Is 5q deletion in de novo Acute Myelogenous Leukemia (AML) with excess blasts a surrogate marker for the cryptic t(7;21)(p22;q22)? A case report and review of literature

•Cryptic or semi-cryptic translocation, t(7;21)(p22;q22) is a rare yet recurring abnormality in acute myeloid leukemia (AML).•Majority of cases with t(7;21)(p22;q22) are associated with a 5q deletion.•We propose that 5q deletion seen in de novo AML may be a surrogate marker for the cryptic t(7;21)(p22;q22) translocation.•Identification of this combination of abnormalities is clinical significant since this combination appears to confer adverse prognosis. Although the 5q- syndrome is common in both de novo and treatment related myelodysplastic syndrome (MDS) and the World Health Organization defined 5q- syndrome as a specific type of MDS, it is less common in acute myelogenous leukemia (AML). Recently, it was suggested that AML with diploidy/tetraploidy and/or 5q alterations may be associated with the cryptic translocation, t(7;21)(p22;q22) resulting in RUNX1-USP42 gene fusion and this association may have been underestimated. Here, we report another case of de novo AML with cryptic t(7;21)(p22;q22) associated with a 5q deletion.