Unusual Translocation in a Usual Leukemia: Follow-up from Diagnosis to Hematopoietic Stem Cell Transplant.

The translocation: t (8;21), a RUNX1-RUNX1T1 fusion transcript is one of the most common chromosomal abnormality, seen in 5%-10% cases of acute myeloid leukemia (AML) and is associated with a favorable prognosis. The most frequent association is found with AML with maturation, that is FAB category AML-M2 (22%-50%), followed by AML-M1, and very rarely in other AMLs. We report a case of AML with monocytic differentiation (AML-M5) with t (8;21), which is a very unusual finding in AML-M5. Our case had characteristic morphological findings of AML-M2, however, it turned out to be AML-M5 on immunophenotyping. We highlight the presence of t (8;21) in AML-M5 wherein the patient did not achieve morphological remission at 29 days and succumbed to his illness, thus emphasizing on the unusual association and a food for thought for both the clinician and the hematologist to ponder that t (8;21) can be associated with monocytic differentiation and overall poor prognosis.