Immunoglobulin G4-Related Hypertrophic Pachymeningitis Presenting with Multiple Lower Cranial Nerve Palsies

Abstract

Immunoglobulin G4-related disease (IgG4-RD) is a multi-organ condition that infrequently exhibits neurological involvement. Here, we describe a case of IgG4-related hypertrophic pachymeningitis with multiple lower cranial nerve palsies. A 65-year-old man presented with a 5-month history of hoarseness and dysphagia. A neurologic examination revealed multiple lower cranial nerve palsies. Brain magnetic resonance imaging indicated diffuse dural involvement along the left tentorium and temporal fossa. Serum IgG and IgG4 levels were found to be elevated. Ethmoid polyp biopsy revealed chronic inflammation with moderate lymphoplasmacytic and some eosinophilic infiltration. Up to 60 IgG4-positive cells were observed per high-power field, and the measured IgG4/IgG ratio was approximately 10% to 20%. Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography indicated abnormally high FDG uptake in the left posterior fossa, tentorium, and left temporal fossa, with additional involvement of the lung, iliac artery, and renal artery. Based on these findings, we diagnosed the patient with IgG4-related hypertrophic pachymeningitis and successfully treated the condition with steroids and rituximab. IgG4-RD should be differentiated from distinct conditions presenting with multiple cranial nerve palsies accompanied by pachymeningitis.