Computed tomography and magnetic resonance imaging findings of inflammatory myofibroblastic tumors of the head and neck.

BACKGROUND: Inflammatory myofibroblastic tumor (IMT) is a rare tumor of mesenchymal origin that commonly occurs in the lung. Because of its non-specific clinical and imaging features, IMT is often misdiagnosed as a malignant tumor. There have been few imaging reports on IMT of the head and neck. PURPOSE: To analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of inflammatory myofibroblastic tumors (IMTs) of the head and neck. MATERIAL AND METHODS: Six patients with IMTs of the head and neck confirmed by histopathologic examination were analyzed retrospectively. RESULTS: The mean patient age was 40 years. The tumor locations in the six patients were as follows: left bridge of the nose (one), right infratemporal fossa (two), and left parotid gland (three). Three patients who underwent CT all had soft tissue masses or nodules and no calcification. Bridge of the nose tumor showed a homogeneous isodense nodule and mild homogeneous enhancement. Infratemporal fossa tumor showed a homogeneous low density mass and intermediate homogeneous enhancement. Left parotid gland tumor showed a heterogeneous, mostly low density mass, and intermediate heterogeneous enhancement. T1-weighted images of the parotid gland tumors were hypointense; the infratemporal fossa tumor was isointense. T2-weighted images were mildly hypointense and of mixed hypo- and isointensity in the two parotid gland tumors; the infratemporal fossa tumor was homogeneously mildly hypointense. Heterogeneous intermediate enhancement was demonstrated in one parotid gland and the infratemporal fossa patients and mild homogeneous enhancement in another parotid gland patient. CONCLUSION: The imaging features of IMTs of the head and neck are non-specific. An ill-defined, aggressive mass and variable enhancement on CT and MRI may suggest the diagnosis of IMT. IMT should be included in the differential diagnosis of regional tumors.