Abstract
Inflammatory myofibroblastic tumor (IMT), a rare sarcoma, is primarily treated via resection of the mass. However, in cases of recurrence or unresectable tumors, no standard care exists. While crizotinib, an anaplastic lymphoma kinase (ALK) inhibitor, is only approved for non-small-cell lung cancer with ALK mutation, it is reportedly effective for other malignant tumors with ALK mutation. We herein report a case involving a 37-year-old woman with retroperitoneal IMT with ALK mutation, who experienced recurrence after complete resection, in whom crizotinib treatment resulted in complete response. ALK-inhibitor efficacy against malignancies with ALK mutations should be investigated in future.