To improve the understanding of IgG4-related intracranial disease.

The clinical, radiographic, and pathological features, diagnosis, differential diagnosis, treatment, and prognosis of IgG4-ralated intracranial diseases were summarized by describing the clinical course of one patient.

A 22-year-old woman presented with headache and decreased vision of left eye 10 months ago. She lost vision of her left eye 6 months ago and her left eyeball was fixed. MRI suggested a space-occupying lesion in the left orbit. The histopathological features were dense lymphoplasmacytic infiltrate, IgG4+ plasma cells >50/high-power field, and IgG4(+ )/IgG >10%. Her symptoms did not change after treatment with full-dose glucocorticoid and low-dose immunosuppressant. She stopped her drugs 2 months ago. Her vision of right eye decreased suddenly half a month ago and her headache became more serious. She totally lost her vision of right eye and suffered from polydipsia, polyuria, and hypernatremia 5 days ago. MRI suggested abnormal signals in the right optic nerve, paranasal sinuses, sellar region, left temporal lobe, and adjacent meninges. The examination of cerebral spinal fluid (CSF) was normal. Her vision of right eye recovered to 0.3 gradually after high-dose glucocorticoid pulse therapy combined with cyclophosphamide pulse therapy. Her headache disappeared and urine volume decreased. Her serum sodium turned to normal. Forty days later, MRI was repeated, which revealed that the new-onset lesions were almost normal.

IgG4-related intracranial disease could involve many regions without extracranial symptoms. This disease may progress very quickly in some cases and timely treatment could avoid irreversible damage.