Case report: inflammatory myofibroblastic tumor of the duodenum.

INTRODUCTION: We report a very rare case of inflammatory myofibroblastic tumor of the duodenum. A 16-year-old boy underwent esophagogastroduodenoscopy for intermittent epigastric pain, night sweats, and malaise. CASE REPORT: An exophytic mass lesion was found in the first part of the duodenum, but biopsies were non-diagnostic. Computed tomography confirmed a 60-mm mass with no lymphadenopathy, and the patient underwent surgical resection. Histology revealed spindle cells with the morphological and immunophenotypical profile of myofibroblasts on a background of mixed inflammatory infiltrate, typical of inflammatory myofibroblastic tumor. Six months after surgery, the patient developed a recurrence, and this was successfully treated by immunosuppression. Currently, the patient is asymptomatic, and there is no radiological or pathological evidence of disease.