Intracranial IgG4-related Disease: Insights from Two Cases

Area of Science:

• Neurology
• Immunology
• Rheumatology

Background:

• Immunoglobulin G4-related disease (IgG4-RD) is a rare fibroinflammatory condition.
• Central nervous system (CNS) involvement is rare (2-4%), often mimicking other diseases and causing diagnostic delays.

Purpose of the Study:

• To illustrate the diverse presentations of CNS IgG4-RD.
• To highlight diagnostic and therapeutic considerations for this rare condition.

Main Methods:

• Case report 1: A 29-year-old male with seizures, diagnosed with dural IgG4-RD via histopathology (IgG4:IgG ratio 20%) and treated with corticosteroids and methotrexate.
• Case report 2: A 44-year-old female with hypophysitis and multisystem involvement, diagnosed with probable IgG4-RD and treated with steroids, methotrexate, and desmopressin.

Main Results:

• Case 1 showed complete radiological resolution and seizure control after treatment.
• Case 2 experienced clinical and radiological improvement with normalized IgG4 levels.
• Both cases demonstrated responsiveness to immunosuppressive therapy.

Conclusions:

• CNS IgG4-RD exhibits significant clinical heterogeneity, from isolated pachymeningitis to multisystem hypophysitis.
• Lower IgG4:IgG ratios (e.g., 20%) can be diagnostically relevant in meningeal disease.
• Corticosteroids and methotrexate are effective first-line treatments for CNS IgG4-RD, necessitating organ-specific diagnostic flexibility and long-term management.