A case report of Immunoglobulin-G4-related hypertrophic sclerosing pachymeningitis.

IgG4-related diseases (IgG4-RD) are a group of chronic progressive autoimmune diseases of unknown etiology that are increasingly recognized as an important pathophysiological basis for a variety of systemic diseases. It is thought to involve almost any organ of the body, but the involvement of the central nervous system is relatively rare. We report the case of a 56-year-old male patient admitted to the hospital d recurrent dizziness and nausea for more than 3 months. The preoperative imaging was misdiagnosed as a meningioma, with this lesion demonstrated localized inhomogeneous thickening of the meninges in the left parietal region on T2-weighted and T2 fat suppression sequences with localized nodular changes. The patient's final pathologic diagnosis was IgG4-associated sclerosing thick encephalitis. The diagnosis of IgG4-associated hypertrophic pontine meningitis is challenging. Clinically, IgG4-associated sclerosing diseases usually present as mass-like lesions, which can be easily misdiagnosed as neoplastic lesions due to their similar appearance. These fundamentally recognized autoimmune disorders respond well to corticosteroid therapy. Therefore, accurate detection of IgG4-related disease is critical to prevent patients from undergoing unnecessary surgery.