Purpose or Case Report: Inflammatory Myofibroblastic Tumor (IMT) is now considered a distinct entity and a true neoplasm within the heterogeneous group of inflammatory mass-forming tumors. It is now recognized as a fibroblastic/myofibroblastic neoplasm with intermediate biological potential. It occurs predominantly in children. Abnormalities on Chromosome 2p23 with a rearrangement of the ALK (anaplastic lymphoma kinase) locus causes abnormal tyrosine kinase receptor expression. Chromosomal abnormalities suggest a clonal origin and not just a reactive process or “pseudotumor,” as these masses have been categorized in the past. Up to sixty percent of inflammatory myofibroblastic tumors express ALK which may help establish the diagnosis of the inflammatory mass as an IMT. The masses can occur in a variety of locations and have non-specific imaging findings, which will be reviewed.

We present three cases, each in a different location:

Case 1: 7 year old female presents with chronic cough and persistent right middle lobe abnormality on chest x-ray with concern for pneumonia or inhaled foreign body. She was found to have a soft tissue mass in her right mainstem bronchus with extra-luminal extension. CT, MR and gross surgical photos of the endobronchial IMT will be presented.

Case 2: 20 month old male presents with hepatomegaly, jaundice and elevated bilirubin, alkaline phosphatase and liver function tests. Ultrasound and MR images of the pancreatic head IMT causing biliary obstruction will be presented.

Case 3: 13 year old male presents with back, leg and pelvic pain. MR, CT and gross surgical photos of the right posterior pelvic sidewall IMT, which had evidence of nerve entrapment at biopsy, will be presented.
The imaging, pathological and surgical findings from these patients, where available, will be presented and reviewed.

We suggest that the radiologist consider Inflammatory Myofibroblastic Tumor in the differential diagnosis for inflammatory and fibrous lesions in children.
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