Abstract Details

Title IgG4-Related Hypertrophic Pachymeningitis Mimicking Neuromyelitis Optica: a Case Report

Topic Autoimmune Neurology

Presentation(s) P10 - Poster Session 10 (5:00 PM-6:00 PM)

Poster/Presentation
Number 8-004

Objective To describe a case of IgG4-related hypertrophic pachymeningitis (IgG4-RHP) as a differential diagnosis of Neuromyelitis Optica (NMO).

Background IgG4-RHP is a rare fibroinflammatory condition characterized by dura mater thickening associated with IgG4-related disease (IgG4-RD). The typical presentation includes headache, cranial nerve palsy, and visual disturbances due to the compression of neurovascular structures. Most patients present elevated plasma and cerebrospinal fluid (CSF) levels of IgG4. The gold standard for diagnosis is histopathology, which may show lymphoplasmacytic infiltration of IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis.

Design/Methods Not applicable.

Results A 31-year-old female patient with controlled hypertension presented with blurred vision in the left eye, which had been progressively worsening for 1 year, accompanied by pulsatile headache in the left temporal region. She sought emergency care due to an acute episode of pain and blindness in the left eye, without deficits in the right. On physical examination, there was an absent direct photomotor reflex on the left and an absent indirect response on the right, with mild proptosis on the left. She was unable to count fingers on left eye field testing and could only perceive light. There was partial paresis of the left inferior oblique muscle. Orbital MRI showed asymmetric hyperintensity of the left optic nerve, suggesting NMO on the left. Normal levels of IgG4 were found in both serum and CSF, along with negative results for oligoclonal bands and anti-aquaporin 4 antibodies. Due to persistent symptoms, further investigation included a neurosurgical biopsy of the pachymeninges, which revealed IgG4-mediated disease through immunohistochemistry.

Conclusions IgG4-RHP shares clinical and pathological features with other forms of hypertrophic pachymeningitis. The typical presentation of NMO may be confused with IgG4-RHP, even in the presence of normal serum and CSF IgG4 levels. Therefore, meningeal sample analysis is crucial for confirming the diagnosis.

Authors/Disclosures
Carolina Matté Dagostini PRESENTER	Miss Matté Dagostini has nothing to disclose.
Artur Vestena Rossato	Mr. Vestena Rossato has nothing to disclose.
Eduardo G. de Almeida	Mr. de Almeida has nothing to disclose.
TAIS L. DENICOL, MD	Miss DENICOL has nothing to disclose.
Marlise D. ribeiro, PhD	Prof. ribeiro has nothing to disclose.
Liselotte Menke Barea, MD	Mrs. Menke Barea has nothing to disclose.

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