FLT3-internal tandem duplication in a pediatric patient with t(8;21) acute myeloid leukemia.

Patients diagnosed with t(8;21)-acute myeloid leukemia (AML) are currently considered to have good prognoses, but about half of these patients relapse. FLT3-internal tandem duplication (ITD) is generally thought to be strongly associated with poor prognosis in AML, but is rarely reported in patients with t(8;21)-AML. Expression of the neural cell-adhesion molecule (CD56) is also associated with a significantly shorter complete remission duration and survival in patients with t(8;21)-AML. Patients with t(8;21)-AML expressing CD56 have been reported to exhibit a higher incidence of granulocytic sarcoma (GS), and t(8;21)-AML with GS results in a less favorable prognosis than AML with this translocation alone. Here, we report on a 15-year-old girl with t(8;21)-AML having both CD56 expression and FLT3-ITD. This patient underwent unrelated donor bone marrow transplantation and achieved complete remission, but thereafter presented with obstructive jaundice caused by GS compression of the common bile duct without bone marrow invasion at relapse. Autopsy revealed multiple nodules of the stomach membrane and invasion into the head of the pancreas. For earlier detection of relapse, we suggest that it would be useful to examine existence of GS in CD56-positive t(8;21)-AML patients at diagnosis and hematologic remission. Even though t(8;21)-AML is less likely to co-occur with FLT3-ITD in pediatric patients, this report suggests that prognostic factors, including FLT3 and KIT genes and the surface marker CD56, should be analyzed in these patients.