Imaging and clinical characteristics of intracranial lesions caused by IgG4-related ear disease

HAN Shaohe; YU Shudong

doi:10.20258/j.cnki.1006-9011.2026.01.005

Abstract：Objective To investigate the clinical and imaging characteristics of intracranial lesions caused by IgG4-related middle ear disease(IgG4-related disease,IgG4-RD),in order to provide evidence for early and precise intervention and to re-duce complications.Methods A retrospective analysis was performed on three cases of intracranial involvement secondary to IgG4-RD of the ear.All cases met established diagnostic criteria and were confirmed through clinical manifestations and histopa-thology.Each patient underwent routine temporal bone CT and middle ear/cranial MRI with DWI sequences.Imaging findings were compared with clinical features.Results All three patients presented with hearing loss in the affected ear(ranging from moderate to profound),accompanied by otalgia and headache.Temporal bone imaging findings were as follows:CT demon-strated diffuse soft-tissue-density opacification within the middle ear cavity.Mild osseous erosion with poorly defined margins was observed in the vestibule and semicircular canal regions.The extent of involvement and imaging characteristics differed markedly from those of cholesteatoma.MRI revealed abnormal soft-tissue signals in the tympanic cavity and mastoid.Lesions showed high signal intensity on T1-weighted images and variable signal intensity on T2-weighted images(either high or relatively low).Contrast-enhanced MRI demonstrated marked enhancement,either homogeneous or heterogeneous.DWI showed relatively high signal intensity(cholesteatoma typically demonstrates markedly high signal),while,ADC values were similar to adjacent nor-mal brain tissue(cholesteatoma exhibits significantly reduced ADC).Intracranial MRI findings included diffuse meningeal thick-ening,peripheral or ring enhancement distinct from cholesteatoma-related brain abscess,and diffuse cerebral parenchymal swelling.Conclusion Patients with intracranial lesions secondary to middle ear IgG4-RD commonly present with moderate to profound hearing loss and headache.Characteristic imaging findings include focal osseous destruction of the temporal bone with ground-glass-like margins on CT.MRI features inflammatory soft-tissue changes,with DWI showing relatively high signal.Intra-cranial MRI demonstrates diffuse inflammatory changes with peripheral lesion enhancement.