ALK and inflammatory myofibroblastic tumor: At present, the specific pathogenesis and etiology of IMT remain uncertain and might be connected with the following factors (4, 7, 10, 11): chronic inflammatory stimulation resulting from bacterial and viral microorganisms (mycobacteria, hepatitis B virus, Corynebacterium, Epstein–Barr virus, EBV, and human papillomavirus), history of bladder trauma or long-term use of hormone therapy, and rearrangements of the anaplastic lymphoma kinase (ALK) gene located on chromosome 2p23 (which occur in ~50% of IMTs).