Pulmonary inflammatory myofibroblastic tumor mimics lung cancer.

Abstract

The term pulmonary inflammatory myofibroblastic tumor (IMT) has been adopted by the World Health Organization to refer to a variety of pulmonary diseases previously named inflammatory pseudotumor, plasma cell granuloma, fibroxanthoma, fibrous histiocytoma, pseudosarcomatous myofibroblastic tumor, and invasive fibrous tumor of the tracheobronchial tree.1Originally, IMT was regarded as a benign tumor, because its histological features included spindle cell proliferation, accompanied by prominent inflammatory cell infiltration.2Furthermore, this tumor had a response to non-steroidal anti-inflammatory agent treatment. However, evidence has suggested that IMT was a tumor of intermediate malignant potential, including adjacent tissue invasion, metastasis,3and genetic abnormalities.4Therefore, it is important to differentiate IMT from pulmonary inflammatory pseudotumor or sarcoma for the development of therapeutic protocol. To gain further knowledge about IMT, we will discuss two cases with unusual characteristics.