ALK and inflammatory myofibroblastic tumor: IMT is mainly composed of myofibroblastic spindle cells mixed with prominently lympho- and plasmacytic infiltration, and is positive for ALK or cytokeratin.[43] while LGMS has a more uniform histological pattern, with a greater degree of nuclear atypia and more mitotic figures, and it is negative for ALK and cytokeratin at immunohistochemistry.[8]