Acute myeloid leukemia (AML) harboring Fms-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) mutation is associated with shorter remission and higher relapse risk. Several FLT3 inhibitors have been used in clinical trials, but their efficacy in extramedullary disease remains unclear. In the present case, a 56-year-old man was diagnosed with FLT3-ITD mutated AML. Due to bone marrow relapse during consolidation therapy, he underwent salvage therapy and a myeloablative conditioning regimen, followed by peripheral blood stem cell transplantation (PBSCT) from a HLA-matched related donor. Acute graft-versus-host disease (GVHD) did not develop, and complete donor chimerism was confirmed on days 27 and 96 after PBSCT. On day 180, he experienced extensive chronic GVHD and had several subcutaneous tumors in his body, which were diagnosed as myeloid sarcoma by pathological examination. We considered this to be a case of isolated extramedullary relapse, as his bone marrow had maintained complete donor chimerism. Treatment with etoposide and ranimustine produced no effect, and tumor progression continued. We started administration of gilteritinib, a FLT3/AXL inhibitor, after identifying the FLT3-ITD mutation in the tumor. Subsequently, there has been a remarkable regression of the tumors. Gilteritinib can be effective in isolated extramedullary relapse after allogeneic stem cell transplantation.

带有Fms样酪氨酸激酶3（FLT3）内部串联重复（ITD）突变的急性髓细胞白血病（AML）与缓解时间较短和复发风险较高相关。几种FLT3抑制剂已用于临床试验，但它们在髓外疾病中的功效尚不清楚。在本例中，一名56岁的男子被诊断患有FLT3-ITD突变AML。由于巩固治疗期间的骨髓复发，他接受了挽救治疗和清髓疗法，然后从HLA匹配的相关供体进行了外周血干细胞移植（PBSCT）。没有发生急性移植物抗宿主病（GVHD），并且在PBSCT后第27和96天证实了完全的供体嵌合。在第180天，他经历了广泛的慢性GVHD并在体内患有多个皮下肿瘤，经病理检查确诊为髓样肉瘤。我们认为这是一例孤立的髓外复发，因为他的骨髓一直保持着完全的供体嵌合。依托泊苷和雷莫司汀治疗无效，肿瘤进展仍在继续。在确定肿瘤中的FLT3-ITD突变后，我们开始给予Gilteritinib（一种FLT3 / AXL抑制剂）给药。随后，肿瘤明显消退。吉尔替尼可以有效地治疗异基因干细胞移植后的髓外复发。在确定肿瘤中的FLT3-ITD突变后，我们开始给予Gilteritinib（一种FLT3 / AXL抑制剂）给药。随后，肿瘤明显消退。吉尔替尼可以有效地治疗异基因干细胞移植后的髓外复发。在确定肿瘤中的FLT3-ITD突变后，我们开始给予Gilteritinib（一种FLT3 / AXL抑制剂）给药。随后，肿瘤明显消退。吉尔替尼可以有效地治疗异基因干细胞移植后的髓外复发。