Pediatric Inflammatory Myofibroblastic Tumor

  • Etiology: neoplasm of mesenchymal origin with intermediate biologic behavior
  • Imaging: solid, primarily inflammatory or primarily fibrotic in appearance depending upon degree of inflammatory infiltrate vs. stromal component and the stroma can be myxoid or fibrotic, well defined, smooth or lobulated, minority are calcified, 18F-FDG PET avid
  • MRI: inflammatory components on T1WI – hypointense to muscle and on T2WI – hyperintense to muscle, fibrotic components are dark on T1WI and T2WI, heterogenous enhancement
  • Imaging in chest: most commonly solitary mass (95%), can involve mediastinum and pleural space, can be endobronchial
  • Clinical: most common sites – lung / mesentery / omentum, most common benign / low grade malignant lung mass in childhood

Radiology Cases of Inflammatory Myofibroblastic Tumor

CXR and CT of inflammatory myofibroblastic tumor in the chest
CXR AP shows a round opacity laterally in the right lung (above left) which projects in the middle of the chest over the trachea on the lateral (above right). Axial CT without contrast of the chest (below) shows the opacity to be a solid mass without calcification next to the pleura.
MRI of inflammatory myofibroblastic tumor
Coronal T1 MRI without (upper left) and with (upper right) contrast of the abdomen shows a large well circumscribed bi-lobed solid mass that enhances homogeneously in the abdomen and that along with the axial T2 image (below) is shown to not arise from any of the solid organs of the abdomen.

Surgery Cases of Inflammatory Myofibroblastic Tumor

Surgical image of inflammatory myofibroblastic tumor
Surgical image shows a mass with a large number of collateral blood vessels that was intimately associated to the terminal ileum and cecum with the appendix draped across the mass.

Gross Pathology Cases of Inflammatory Myofibroblastic Tumor

Gross pathological image of inflammatory myofibroblastic tumor
Gross pathological image shows a pale solid mass in the center of the lung.