Radiological Features of IgG4-Related Disease in the Head, Neck, and Skull Base

Background: IgG4-related disease (IgG4-RD) is increasingly recognized as a multisystemic, chronic inflammatory process characterized by histologic fibrosis with IgG4-positive plasma cell infiltration. Objectives: The purpose of this study was to characterize the imaging features of patients diagnosed with IgG4-RD in the head and neck, especially the skull base. Methods: Our study evaluated CT and MR imaging features of IgG4-RD in the head, neck, and skull base. Images from 15 patients were retrospectively evaluated for the location, signal intensity, morphology, size, boundary, and pre- and post-contrast MRI performances. Results: The lesions presented as irregular shaped, localized masses, distributed in skull base regions; 93.3% of the lesions were isointensity in T1WI (14/15). A total of 80% of the lesions were iso-hypointense in T2WI (12/15); 60% of the lesions got homogeneous enhancement (9/15); and 46.7% of the patients had cranial nerves dysfunction (7/15). The most likely involved cranial nerve was trigeminal nerves (5/15); 60% of the patients had osteolytic bone destruction or sclerosis (9/15). Conclusion: Typical radiological features of IgG4-RD included T1 isointensity and T2 hypointensity, homogeneous and gradual enhancement pattern in MRI, easy cranial nerve invasion, dura involvement but the absence of brain edema, and the presence of bone remodeling without destruction, blurred lesion boundaries.