Introduction: Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor that involvesvarious organs. Surgery is the mainstay of therapy for this tumor. Approximately half of all IMT cases haveanaplastic lymphoma kinase (ALK) rearrangements
therefore, the ALK inhibitor crizotinib is suggested as apromising treatment for unresectable cases with ALK rearrangements. In cases withoutALK rearrangement,chemotherapy is an alternative treatment for unresectable tumors.Cases report: We report 4 cases of IMT treated in Children Hospital Number 2 since 2018. There wasone case with mesenteric tumor, one with perineal tumor detected at birth, one with inferior mediastinaltumor and one with intestinal tumor. We evaluated ALK expression by immunohistochemistry and ALKrearrangement by fluorescence in situ hybridization (FISH) in 3 cases and all negative. Treatments includedtumor resection or biopsy and chemotherapy with methotrexate (30mg/m2) day 1 and vincristine (1.5mg/m2) day 1 and 7 in a 3 week cycle together with NSAID or steroid for inflammatory control. There was onecase with complete response to surgery and chemotherapy
the other 3 cases ended in death due to tumorrecurrence (3 cases) and metastasis (1 case).Conclusions: IMT has a diverse clinical presentation, appears in many different locations, and theclinical course can progress quickly with high rate of recurrence after incomplete surgical resection. Surgeryis the optimal approach, but in those without complete resection and in those with tumor progression,tyrosine kinase inhibition should be considered if there is ALK rearrangement. In the absence of ALKrearrangement, additional tyrosine kinase rearrangements and other potentially efficacious chemotherapyregimens need to be studied for these patients.