IgG4-related cerebral pseudotumor with perineural spreading along branches of the trigeminal nerves causing compressive optic neuropathy: A case report

RATIONALE: Immunoglobulin G4-related disease (IgG4-RD) is characterized by tumor-like lesions, a dense lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis. IgG4-RD has been described in a variety of organ systems; however, it rarely involves the central nervous system. PATIENT CONCERNS: A 17-year-old woman visited our clinic with a complaint of blurred vision for the past 5 months. She also reported a painless right submandibular mass that had been present for 1 year. Her best-corrected visual acuity (BCVA) was 2.0 LogMAR, with an almost total visual field defect in the right eye. DIAGNOSES: Magnetic resonance imaging (MRI) revealed lobulated parasellar tumors with perineural spreading along branches of the trigeminal nerves causing right optic nerve compression. A craniotomy with tumor removal and submandibular gland biopsy was performed. Histopathological analysis of the tumor revealed stromal fibrosis with atypical lymphoid infiltrations. Histopathological and immunohistochemical analysis of the submandibular gland confirmed the diagnosis of IgG4-RD. INTERVENTIONS: The patient was administered 500mg/d of pulse methylprednisolone for 3 days, 500mg of intravenous rituximab every 2 weeks (for a total of 2 doses), and 500mg of intravenous pulse cyclophosphamide every month (for a total of 3 doses). OUTCOMES: Two months after the initiation of immunosuppressive therapy, the patient's BCVA returned to 0.1 LogMAR with visual field defect recovery. The follow-up MRI showed the almost complete disappearance of the previously contrast-enhanced lesions. LESSONS: Herein, we report a rare case of IgG4-RD presenting as a parasellar tumor and present a review of the related literature. Based on the case report, we propose that aggressive therapy with glucocorticoid, rituximab, and cyclophosphamide may potentially be useful for treating such cases.