Abdominal inflammatory myofibroblastic tumor: a clinicopathologic study with reappraisal of biologic behavior

Background and Purpose: Inflammatory myofibroblastic tumor (IMT) is a proliferative lesion of controversial nosology and uncertain prognosis. In an attempt to acquire further understanding of pathogenesis and biologic behavior, we surveyed abdominal IMTs managed over the last 12 years at a single institution. Methods: Intra-abdominal IMTs treated between 1995 and 2007 were reviewed concerning demographic, clinical, and pathologic features as well as therapeutic management and outcome. All specimens were reevaluated by histologic examination and immunohistochemistry. Results: There were 7 patients (4 males; age range, 28 days to 14 years). Five lesions were located in alimentary tract: 1 gastric presenting with bleeding, 1 hepatic presenting with a thoracic wall mass, 1 pancreatic and 2 colonic presenting with obstructive symptoms. One splenic IMT was found incidentally. The remaining case arose from the adrenal gland and presented with a palpable mass. The gastric and adrenal IMTs had evidence of a previous or concomitant infectious setting. Five lesions were excised. The pancreatic IMT underwent a drainage procedure followed by steroid administration, and the hepatic lesion received antibiotics. Histopathology revealed characteristic findings of IMT. Expression of anaplastic lymphoma kinase was negative in all cases. At a median follow-up of 6 years (range, 3-15), all children were asymptomatic with no recurrences. The hepatic and pancreatic IMT displayed complete and near total regression, respectively. Conclusion: A benign behavior of abdominal IMTs was observed even in patients not undergoing surgical excision. Although IMT remains a surgical disease, a conservative approach may be reasonable in select cases. (C) 2011 Elsevier Inc. All rights reserved.