Case report: Crizotinib is effective in a patient with ROS1-rearranged pulmonary inflammatory myofibroblastic tumor.

Objectives: Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor and is prevalent among children and adolescents. In recent years, following the emergence of high-throughput sequencing techniques, rearrangements in genes, such as ALK, ROS1, NTRK, RET, and PDGFRβ, have been detected in a considerable proportion of IMT patients. However, the practice of targeted therapy for those patients remains extremely limited. In this study, we report about a 14-year-old boy diagnosed with pulmonary IMT with a mass measuring 12 × 8 cm in the right lower lobe.

Materials And Methods: Immunohistochemistry (IHC) assay and comprehensive next-generation sequencing (NGS) were performed on the biopsied tumor tissue.

Results: The IHC assay revealed an ALK-negative tumor, while NGS detected aTFG-ROS1 rearrangement. The patient achieved continuous remission after treatment with crizotinib (250 mg, bid).

Conclusion: This case broadens the experience regarding targeted therapy forROS1-rearranged IMT and supports the use of broad molecular profiling testing for optimizing therapeutic options.