[Pachymeningitis associated with IgG4 disease]

Area of Science:

• Neurology
• Immunology
• Pathology

Background:

• Hypertrophic pachymeningitis is an uncommon condition with diverse etiologies, including infections, autoimmune disorders, and neoplasms.
• Idiopathic cases may represent undiagnosed IgG4-related disease, a recently recognized systemic inflammatory condition.

Observation:

• A 60-year-old male presented with headache and bilateral episcleritis, partially responsive to corticosteroids.
• Brain MRI revealed dural thickening and enhancement, consistent with pachymeningitis.
• Meningeal biopsy demonstrated fibrosis, lymphoplasmacytic infiltrate, and elevated IgG4-positive plasma cells (>10 per HPF).

Findings:

• The patient's symptoms and MRI abnormalities significantly improved after treatment with rituximab.
• This suggests a strong association between hypertrophic pachymeningitis and IgG4-related disease.
• Elevated serum IgG4 levels can support the diagnosis when combined with characteristic MRI findings.

Implications:

• Recognizing hypertrophic pachymeningitis as a potential manifestation of IgG4-related disease is crucial for accurate diagnosis and effective treatment.
• MRI findings, coupled with IgG4 plasma cell quantification, aid in diagnosing IgG4-related pachymeningitis.
• Rituximab offers a promising therapeutic option for IgG4-related pachymeningitis, leading to clinical and radiological improvement.