多発脳神経麻痺を呈したIgG4関連肥厚性硬膜炎の1例

Multiple Cranial Neuropathies in a Patient with IgG4-related Hypertrophic Pachymeningitis: A Case Report

症例は75歳女性。多発脳神経麻痺を呈したIgG4関連肥厚性硬膜炎を経験した。約10カ月の経過で左聴神経障害，拍動性の左側頭部痛，右迷走神経・副神経障害が順次出現し，その後，突然両側視力障害を呈した。造影頭部MRIで硬膜肥厚を認め，診断目的で脳硬膜生検を行った。病理所見では，肥厚した硬膜の線維性変化，リンパ球を中心とした炎症細胞浸潤およびIgG4陽性形質細胞浸潤を認め，また一部に硬膜動脈周囲の炎症細胞浸潤を伴っていた。ステロイド療法により視力は急速に回復し，画像所見でも肥厚した硬膜の改善がみられた。本症例の臨床像は特発性肥厚性硬膜炎であり，病理組織は近年提唱されているIgG4関連疾患の像を呈していた。これまで特発性肥厚性硬膜炎と考えられていたものの中には，このようなIgG4関連疾患が含まれていると考えられる。

Abstract

We describe the case of a 75-year-old woman who presented with acute loss of vision. She experienced subacute headache, hearing loss on the left side, hoarseness, and dysphagia during the previous 10 months. On admission, she had bilateral loss of vision, without any ophthalmological abnormalities, and multiple cranial nerve palsies, including left hearing loss and right IX, X, and XI nerve palsies. Head magnetic resonance imaging with contrast enhancement revealed hypertrophic pachymeningitis. Laboratory findings showed no abnormalities except for an increased sedimentation rate and increased C-reactive protein levels. A biopsy of the dura mater was performed, and histopathological analysis revealed inflammatory thickening of the dura mater with plasma cell infiltration; the infiltrating cells were immunoreactive to an anti-IgG4 antibody, thereby indicating an IgG4-related disorder. Furthermore, the histopathological analysis revealed evidence of vasculitis in both veins and arteries. After corticosteroid treatment, her visual acuity dramatically improved. Acute loss of vision with multiple cranial nerve palsies may be an uncommon presentation of IgG4-related hypertrophic pachymeningitis. However, it should be recognized that these conditions might be underdiagnosed. The possibility of central nervous system involvement in IgG4-related disorders should be considered in patients with multiple cranial nerve neuropathies associated with hypertrophic pachymeningitis, even in the absence of systemic sclerosis symptoms. In our case, early treatment with corticosteroids showed immediate effectiveness in correcting the visual symptoms.

(Received October 3, 2013; Accepted November 13, 2013; Published July 1, 2014)