Intracranial Immunoglobulin G4-Related Disease Presented as Hypophysitis and Pachymeningitis: A Case Report.

Immunoglobulin G4-related disease (IgG4-RD) is a fibro-inflammatory disorder characterized by tumefactive lesions containing IgG4-positive plasma cells. It affects diverse organs in the head and neck, but mainly the lacrimal glands, orbital tissues, thyroid glands, pituitary glands, and meninges. The involvement of the pituitary glands and meninges is uncommon; therefore, it may be misdiagnosed as infectious or malignant. IgG4-related hypophysitis (IgG4-RH) causes hypopituitarism, headache, and visual disturbances. IgG4-related hypertrophic pachymeningitis (IgG4-RHP) causes visual or hearing impairment, motor or sensory alterations, headaches, and seizures. Biopsy is the most definitive diagnostic method; however, it can be invasive and unnecessary in certain cases. IgG4-RH shows an enhanced sellar mass/thickened pituitary stalk, whereas IgG4-RHP shows linear dural thickening or a bulging mass. Currently, long-term steroid therapy is the first-line of treatment. Here, we report a case of intracranial IgG4-RD diagnosed as IgG4-RH and IgG4-RHP based on serological examination, imaging findings, and response to steroid treatment.