Targeted therapy for medullary and extramedullary relapse of FLT3-ITD acute myeloid leukemia following allogeneic hematopoietic stem cell transplantation.

We report a case with extramedullary tumors affecting the supraclavicular region that presented as a relapse of acute myeloid leukemia (AML) with FLT3-ITD mutation after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Treatment with gilteritinib resulted in remarkable response with disappearance of both the medullary and extramedullary tumors. Subsequently, a 2nd allo-HSCT was performed in an attempt to cure his AML and complete molecular response has been sustained with gilteritinib resumption without worsening GVHD. Targeted therapy with gilteritinib for medullary and extramedullary relapse of FLT3-ITD AML could be effective and suitable as a bridging therapy for allo-HSCT.