ALK and inflammatory myofibroblastic tumor: Studies have reported that approximately 50% of IMTs have alterations in the ALK gene located on chromosome 2p23.4) ALK IHC is the most useful marker because the reactivity of neoplastic spindle cells with ALK corresponds strongly to the presence of a clonal ALK rearrangement.14) In this case, ALK positivity on IHC confirmed the presence of an ALK rearrangement, which was the decisive factor in the diagnosis of IMT.