ROS1 and inflammatory myofibroblastic tumor: ROS1 rearrangements have been reported in around 9% to 13% of IMT, all ALK-negative cases.[22,25] Clinical cases of children/adolescents with pulmonary IMT with a TGF-ROS 1 rearrangement have also been described in the literature, all benefitting from treatment with crizotinib (250 mg) in terms of a significant reduction in tumor size.[25–27]