Immunoglobulin G4-related disease presenting as an intracranial mass extended from the infratemporal fossa

Background : Neurological manifestations in immunoglobulin G4-related diseases (IgG4-RD) are rare and documented in <2% of cases. It commonly involves pachymeninges forming hypertrophic pachymeningitis and rarely forms tumor-like masses. Case Description: We present our experience with a biopsy-proven case of IgG4-RD presenting with an intracranial extradural tumor-like mass infiltrating the temporal lobe. The patient was treated with high doses of corticosteroids followed by slow tapering. The neurological manifestations gradually improved and resolved after 2 months with a cerebral MRI showing a significant reduction in the tumoral size. Conclusion: When it comes to intracranial mass, IgG4-RD neuropathy is one of the rarest differential diagnoses for the central nervous system tumors. Early recognition of IgG4-RD and appropriate establishment of its long-term treatment may avoid unnecessary investigations and morbidity.